Recycling and Reuse of Grit Blasting Waste for Composite Materials: Directions, Properties and Physical Chemistry Approaches

Abstract

This study reviews the methods and materials used in industry and ship maintenance to remove rust, marine deposits and paint from ships. It also reviews how this waste is transferred and repurposed into useful materials. The notion of recycling in this field of application represents the reuse of the waste blend of the abrasive grit material along with the mineral residues, antifouling agents and coatings removed in meaningful applications. They are used in building construction materials, road construction blends, insulation surfaces, renewed composites and coatings. The main concern of the experts is the presence of heavy metals that limit the applications of the waste mixes. Therefore, a thorough characterization of the waste stream is paramount to ensure its safety and suitability for repurposing. Furthermore, the study investigates the potential for upcycling these waste materials into higher-value products, moving beyond simple reuse to create new economic opportunities. Ultimately, the goal is to convert a former waste stream into a valuable resource, aligning with circular economic principles.

1. Introduction

The blasting process is widely used in the marine repair industry, which, among others, produces large quantities of blasting waste containing coatings, heavy metals and antifouling agents. Abrasive blasting includes propelling materials like steel grit, sand or other abrasive media against a surface to remove rust, paint or other contaminants [1]. Dry abrasive blasting applies natural minerals, mineral slags or metallic grits [2]. Wet blasting methods, such as hydraulic blasting, slurry blasting and ultra-high-pressure water jetting, are increasingly used because they allow for a serious reduction in dust emissions and spent abrasive generation [3,4]. The resulting waste generated from the grit blasting process typically contains the spent abrasive contaminants from the blasted surface such as rust, paint chips, etc., together with other residues [5].

The grit is an abrasive blasting material (ABM) used for the preparation of metal surfaces in shipbuilding or maintenance and repair, one step before the application of multiple coatings [6]. ABM is a hazardous waste that exposes workers to serious health risks and the environment to real danger, especially for natural resources, such as water and land. Considering that the total amount of ABM increases every year worldwide, there is an urgent need to reduce these quantities. Incineration is a non-eco-friendly process, producing other pollutants, either by air emissions or as residual waste [7]. However, the recycling of ABM has serious potential for creating various useful byproducts. Therefore, ABM can be reused as a feedstock in a productive process step or for the recovery of a reusable product. The main characteristics abrasives must have are efficiency, productivity, high recyclability, and environmental friendliness, in line with sustainable development goals [8].

A very important aspect of industrialized waste management is the recycling of the grit blasting waste, which is produced by abrasive blasting procedures [9]. Several methods for the recycling of grit blasting waste are used in the industry, such as separation and reuse of abrasive media, metal recovery, cement and concrete applications, and, finally, landfill diversion via stabilization [9]. These recycling methods are crucial not only for mitigating the environmental impact by reducing the volume of waste sent to landfills but also for recovering valuable materials and conserving natural resources, thereby contributing to a more sustainable and circular economy [10]. This study reviews recent progress in both the materials and methods used for rust, marine growth, and paint removal in industrial and ship maintenance, and the logistics of transforming the waste generated into useful and valuable resources (Figure 1).

2. Physicochemical Insights into Grit Blasting Waste

The physicochemical properties of grit blasting waste are mainly influenced by two key factors: the type of abrasive material used and the characteristics of the surface being blasted. It is mentioned that this waste typically consists of a complex mixture of the original abrasive particles—often degraded or fractured—and the contaminants removed from the blasted surface. A thorough understanding of these properties is crucial for effective waste management, environmental evaluation, and exploring possibilities for recycling or reuse [11,12].

2.1. Physical Characteristics

The physical characteristics of grit blasting waste include the particle size and distribution, the particle shape, the density, the porosity, and the moisture content [13]. Regarding the particle size and distribution, abrasives typically exhibit a smaller and more varied particle-size distribution than fresh media, as a result of fragmentation during impact. The presence of finer particles can lead to higher dust generation and an increased risk of inhalation hazards. Taking into account the particle shape, the potential original abrasive’s shape alterations—whether spherical shot or angular grit—can influence handling characteristics and, if the material is reused, may impact the effectiveness of subsequent blasting operations. Moreover, the bulk density of the waste varies significantly, affected by the original abrasive’s density and the type and amount of mixed or embedded contaminants. It has been mentioned that certain abrasive materials or accumulated contaminants may exhibit porosity, affecting their ability to retain moisture and potentially enhancing the leaching of contaminants. Considering the moisture content, depending on the dry or wet grit blasting method used and storage conditions, the waste can have varying moisture levels. Wet blasting produces a slurry that requires dewatering, impacting disposal or processing costs [14].

2.2. Chemical Composition

Initially, grit blasting waste is classified into six different categories. The first categorization is based on material composition. Considering that the grit blasting waste mainly consists of the abrasive material used during the blasting process, it should be mentioned that this waste varies based on the type of abrasive employed. Therefore, this category, as seen in Figure 2, includes (i) mineral abrasives such as garnet, sand (silica), or aluminum oxide; (ii) synthetic abrasives, such as plastic beads or silicon carbide; and (iii) metallic abrasives, such as steel grit, steel shot, or copper slag. Subsequently, it is noticed that the composition of the waste is a complex waste stream due to the fact that it contains the spent abrasive and the removed surface material (rust, paint, coatings) (

Table 1. Classification of industrial common ABMs.

Agricultural Waste	Natural Minerals	Mineral Slag	Metallic Grits	Synthetic Grits
Walnut shells	Sand	Fe-Ni slag	Steel	Plastic beads
Corn cob	Alumina	Scrap metals	Zn	SiC
Plum stones	Silica		Ni
Apricot stones	Zeolites		Co
Peach stones	Garnets		Cu
	Glass/Ceramics		Fe

) [13]. Moreover, biodegradable and naturally abrasive materials, like agricultural waste, particularly useful for gentle cleaning, delicate surfaces, and polishing applications, are also included in Table 1.

Natural and organic materials, such as walnut shells and ground corn cobs, are often used for abrasive blasting. Powder from ground apricot, peach, and plum stones are also popular options. These natural materials are a gentler alternative to harsher blasting media, making them ideal for cleaning delicate surfaces without causing damage. The specific material and particle size used depend on the surface being treated. The usual situation is that the residues from a process (or several steps of a process) that results in a multi-component composition which would demand particular manipulation, to be useful again. Therefore, the selection of a recycling or reuse method heavily depends on the composition of the material, as different materials require different approaches. The fundamental research is broad and cannot easily cover all feedstocks; the precision required for investigation narrows the options studied, as shown in each case reviewed in this text [12].

The second categorization refers to the hazardous, mixed nature. The chemical composition is perhaps the most critical aspect, directly dictating the waste’s potential environmental and health hazards. The bulk of the waste consists of the original abrasive material. Silica is a major component of sand and some types of crushed glass, with crystalline silica posing a serious health risk due to its association with silicosis [15]. Iron oxides are commonly found in steel grit, certain slags, and steel shot, while aluminum oxide is a typical ingredient in manufactured abrasives. Garnet, a natural mineral, consists of various silicates such as iron aluminum silicate. Calcium carbonate is present in some natural abrasives. Beyond these base materials, a significant source of hazard arises from contaminants removed from the blasted surface. These contaminants vary depending on the substrate and its usage history. Heavy metals—including Pb, Cr, Zn, Cd, Cu, and Ni—are frequently detected, often originating from old coatings such as anti-fouling or anti-corrosion paints or from the substrate itself [16]. Chlorides may be introduced either through the abrasive material (e.g., certain slags) or from the environment, particularly in marine applications. Elevated chloride levels are of concern, as they can promote corrosion if the waste is reused in construction. Finally, sulfates can be present, originating from industrial coatings or specific types of slag. The hazardousness of the waste is attributed to these elements [13].

In addition to metals, organic pollutants may also be present. These include polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and other organic residues from previous coatings or industrial processes. Regarding paints for ships, they may be pigments with mineral oxides and, nowadays, more often, polyurethane and epoxy systems. As for other coatings applied for the protection of the hull, antifouling agents, hardening agents or sealers may be found as well [17]. Regarding other health issues, in case silica-based materials (like sand) are used as abrasives, there is a risk of airborne crystalline silica, a known respiratory hazard (silicosis). Waste may contain toxic substances from the coatings, such as volatile organic compounds or asbestos. To combat this issue, the size of the grit material should be taken into consideration as well. Large mean diameters are safer for the respiratory system of the workforce and do not remain suspended in the work atmosphere [18].

2.3. Health and Environmental Concerns

The leaching potential is a key physicochemical property in environmental risk assessment, as it measures the extent to which contaminants—especially heavy metals—can dissolve and migrate into the surrounding environment, such as soil or groundwater, upon exposure to water. The toxicity characteristic leaching procedure is widely used to assess whether a waste material is hazardous; the leachability of specific toxic constituents is evaluated. If the concentration of leached contaminants surpasses regulatory limits, the waste is deemed hazardous and must be managed through specialized disposal methods [19]. It is mentioned that several factors influence leaching behavior, including the pH of the leachate, the redox potential of the environment, the presence of complexing agents, and the chemical speciation of the contaminants. For instance, some metals are more mobile under acidic conditions. During grit blasting, airborne particulate matter (dust) can pose health risks to workers, including respiratory problems. Proper personal protective equipment, area ventilation, and dust control measures are essential. Workers involved in grit blasting are at risk of exposure to harmful substances (e.g., Pb, SiO₂, volatile organic compounds), which necessitates strict safety protocols such as respiratory protection, ventilation, and monitoring of exposure levels. Breathing in micro- and nanoparticles can lead to various health issues, particularly affecting the respiratory and cardiovascular systems. Even if the substances are inert (like SiO₂), their tiny size makes them irreversible to remove [20].

Improper disposal of grit blasting waste, especially those containing heavy metals or hazardous materials, can lead to soil and groundwater contamination. The Environmental Protection Agency and other local regulatory bodies often mandate that grit blasting waste be managed according to hazardous waste regulations, in case it contains toxic substances. Non-hazardous waste is typically disposed of in industrial landfills, whereas hazardous wastes require specialized treatment or disposal methods, such as incineration, pretreatments, or stabilization (Figure 3) [13].

2.4. Waste Management and Recycling

Proper waste characterization is necessary to determine whether grit blasting waste is hazardous or non-hazardous. This is typically carried out using the toxicity characteristic leaching procedure, which decides on the leaching of hazardous substances [13]. Then, the necessary recycling may provide recycling of abrasives, metal recovery, and beneficial secondary use. Regarding the recycling of abrasives, some grit blasting media, like steel shot or garnet (mineral and metallic), can be recycled and reused multiple times in marine maintenance, reducing the total amount of waste produced, a process regarded as internal recycling. Grit blasting waste can be processed to recover metals for reuse in industrial applications. The metal recovery process involves several key steps: collection, screening, cleaning, and sieving to separate and prepare the metal for future use. For example, Cu can be recovered from Cu slag through this process. Considering the beneficial secondary use, some non-hazardous blasting media, like garnets, can be used in construction materials, road base, or cement production.

The high generation rate of grit blasting waste during the repair procedures and the toxicity of this blasting waste are the main points underlined in the literature. Alternative reusing and recycling management are discussed widely [13]. Mineral compositions of ABM waste produced from dry abrasive blasting include Al₂O₃, CaO, K₂O, MgO, SiO₂, Fe₂O₃, Na₂O, ZnO, Cr₂O₃, TiO₂, MnO, Cu, As, Cd, Co, Cr, Mo, Ni, Pb, and SO₃ [13]. The subsequent management practices must be followed based on the composition and hazard level, since recycling or reuse takes into consideration compliance with health and safety regulations to minimize environmental and human health impacts. These practices relate to source reduction, containment, and waste segregation. Considering the source reduction, using recyclable or less hazardous abrasives can reduce the amount and hazard level of waste generated. Taking into account the containment, enclosures, and dust suppression systems during blasting operations help minimize waste dispersion and protect workers. Regarding waste segregation, keeping hazardous and non-hazardous waste streams separate facilitates recycling and proper disposal.

In the study of Rees et al., the peeling paint from certain ships and vessels is analyzed. The X-ray fluorescence (XRF) recordings have, as the main goal, the detection of Pb, Cu, and Zn, metals with high environmental and human health concerns. Contamination from paint flaking off is a real environmental threat. The hazardous waste of peeling paints for many aged boats must be monitored as a issue of high concern [21]. It was proven that Pb is the greatest concern from both environmental and human health perspectives. Turner et al.’s study deals with the hazardous paint flaring off from ship repairs. An XRF technique is mainly used for detection and quantitative measurements of the concentration of substances such as Pb, Zn, Sn, Cr, and separation from organic compounds. ICP-MS is suggested as an additional analytical tool for a full risk environmental assessment for paint waste from ship works [22].

An efficient, simple, and feasible strategy for recycling waste coming from zinc-rich paint residue is presented in the work of Xing et al. The aforementioned waste was generated via the anticorrosion spraying of steel-structure protective coatings in the ship industry. Electrowinning and oxidative alkaline leaching processes were applied for the recovery of the residue. The obtained results revealed that adjusting the parameters of temperature, alkaline concentration, current concentration, and gelatin dose (refined the grain) played a crucial role in the high efficiency of the method. Moreover, the results from the thermal and composition analysis of the leaching residue indicated that the proposed co-processing in a cement kiln can be used for disposing of the leaching residue of zinc paint residue and therefore can be used for its recycling [23].

The research by Rachmant et al. deals with the sustainability of a shipyard during the overall repairs of a ship. Ship repairs are linked to chemicals and toxic substances and of course to a high concentration of hazard waste, which contains heavy metals, surfactants, phenol compounds, etc. The impact of these byproducts in the ecosystem is significant and extremely harmful for the coastal environment near the shipyard [24]. In Guth et al.’s study, the exposure of workers to Pb during abrasive blasting procedures is investigated, the main substance of the painted metallic surfaces. Blood Pb and dermal Pb levels in the waters are considered the main measurements responsible for protecting workers’ health. Respirable silica, chromates and heavy metals are some of the dangerous substances. The blood lead level in certain personnel has increased. Research to gain a deep understanding of the sandblasting waste is mandatory because the exposure to these metals, like lead, is high [25].

The co-processing of hazardous waste as paint sludge (coming from the automotive industry) in a cement kiln is suggested by Gautam et al. The co-processing trials were monitored to measure emission levels of metals and heavy metals (Ti, Cr, Co, Cu, Mb, Sb, Cd, Ni), dust, and chemical substances such as benzene, ammonia, HCl, organic compounds (such as toxins and furans). Co-processing is proposed as a better option than the typical incineration or landfill of the waste. A high temperature of 1450–1500 °C “helps” to obtain a baseline emission level. Finally, different kinds of waste have the same content of emissions, in terms of energy needed for treatment or solvents needed for processing [26]. Katsikaris et al. deal with the recycling of the Fe-Ni waste slag of blasting procedure, yielded by the dry method, from the ship-cleaning procedures in the shipyards. Regarding the particle-size analysis of the Fe-Ni slag, it ranged between 150 and 1400 μm and demonstrated that the life cycle of the slag lasts three times as long with 80% feasibility. The conductivity and the organic content of the slag remained almost the same compared to the first procedure cycle [27].

The abrasive blasting industry is an operation with high exposure to silica because all abrasive media contain a high content of silica sand. In the review by Zulkarnain et al., a “green” blasting media is studied, for the replacement of free silica, as a media obeying the “Principles of Green Chemistry” for sustainable sandblasting procedures (Figure 4). While the term “green” is often associated with environmentally friendly options, in the context of abrasive media, it specifically refers to materials that align with the principles of green chemistry. These principles include waste prevention, using fewer and safer chemicals, and generally being more environmentally benign. Therefore, even a naturally occurring material like silica (silicon dioxide) can be considered a “green” abrasive medium because it follows these principles. Moreover, there is a comparison of different blasting techniques, such as the wet blasting technique (with coarse and highly fine media), conventional dry sandblasting, wheel blasting (absence of propellant, gas, or liquid) with recyclable abrasive media, hydro-blasting (pressured stream water) without damaging the surface, and micro-abrasive blasting (usage of small nozzles). “Green” abrasives are the main suggestion for the future of blasting procedures. The impact of “green” abrasives will contribute to waste reduction and, through a life-cycle perspective, will benefit the blasting industry. The worldwide consumption of abrasives is increasing day by day, so the environmental performance of the processes must achieve a low amount of waste, low emissions, and high recyclability [5].

The leaching of Cu and Zn metals from a composite of spent antifouling paint particles was studied in Turner et al.’s research. The leaching of Cu was increased, but Zn decreased with increasing salinity (Cu₂O dissolves in the presence of chloride and Zn acrylates in the presence of seawater cations). The presence of CaCO₃ in the paint composite seems to increase the metal leaching at different temperature conditions. The results have important environmental and biological impacts regarding the disposal of antifouling coating residues. The extent of metal release is high, showing an increase in the leaching of Cu and Zn with a reduction in temperature, under certain conditions [22]. Finally, future research must be carried out on the effects of dissolved organic matter from paint composite materials [28].

In the study by Prabhakaran et al., the paint-sludge ingredients were investigated by thermogravimetric analysis. The sludge was blended with lignite in 70:30, 60:40, and 50:50 percentage ratios, respectively, and the activation energy was computed. The blending of paint sludge with lignite coal shifted the reaction mechanism. XRF confirmed the presence of heavy metals. The co-combustion process was made more effective by paint-sludge blending with lignite coal (principal component analysis). The percentage contribution of paint sludge to degradation was as high as 70.71 wt.% compared to lignite coal. The use of the blending process is indicated for the effective reuse of paint sludge via the co-combustion process. The suggestion is that paint sludge can be used as an energy conservation material and decreases the combustion of fossil fuels [29].

Kotrikla’s review studies the best management practices to eliminate, or significantly decrease, the environmental effects of tributyltin, an organotin antifouling agent for vessels. The removal of tributyltin from shipyard waste and from the sediment is essential and can be approached through the recycling of abrasive materials, use of cleaner means, reuse of spent materials, and substitution of hydro-blasting by vacuum blasting. The concentrations of tributyltin found in shipyards’ wastewaters are very toxic to microorganisms. The solid sandblast waste is usually disposed of in landfills without pre-treatment [30]. Cornelis et al. [31] studied the quality parameters for the reuse of organotin sediments as a secondary non-building material. Ultimately, the recycling of the abrasive materials (sand and metal slag) is suggested, along with the use of cleaner abrasive materials, and the reuse of spent abrasive materials in public/construction works. Techniques such as coagulation–clarification and filtration, solvent extraction, and electrochemical treatment are available and result in the removal of tributyltin [32].

In the research by Hansel, a general overview of the sandblasting procedure is demonstrated. The principal method, the machinery, and the material media used are detailed. Steel is the most common and, due to its long life (it can be recycled up to 200 times), the most preferred material. It is necessary to establish an operating mix and monitor the amount of small, medium, and large particles to ensure the desired surface. On the other hand, Al₂O₃ is the popular choice for tough cleaning jobs. Al₂O₃ is offered in a wide range of sizes, from fine to extra coarse. It can be recycled several times as well. Interior rubber lining on blasting enclosures is also employed. Glass beads are a unique abrasive media developed to remove surface contaminants, without dimensionally affecting the cleaning surface. Glass beads are manufactured from a Pb-free, soda-lime-type glass, and contain no free SiO₂. Their shape is almost perfectly spherical, ideal media for shot-peening uniformity [33].

The study by Rahman et al. involves analyzing the life-cycle assessment of ship dismantling in Bangladesh. The ship-dismantling operations help the local economy by offering raw materials, recycling steel for reprocessing as steel scraps. Of course, the benefit for the environment is obvious, as it means we do not consume natural resources (virgin ores). Secondly, there is a reduction in electricity and natural gas consumption. The torch cutting, a high-energy consumption procedure, and, on the other hand, the rebar production, are all contributing to the perception that ship recycling pollutes the surrounding environment. If we alter some stages of recycling, we can easily avoid high environmental risks [34].

In the paper by Alankaya et al., the abrasive blasting materials are studied for their impact efficiency. The blasting process efficiency and the damage behavior by material type, their geometry or coating perforation depth, and particle velocity during the procedure are the main topics of the study. The main reason for the selection of the type of blasting material is waste reduction and the prevention of pollution through the minimization of waste during the process. The shape of the long rod, the sphere-shaped particles with less mass, and the cubic-shaped geometry are the main geometries studied. Cast Fe and Cu particles are compared to their performance for paint removal. The speed of the material is always a very important factor. The dry-ice blasting method is presented as a new ecofriendly method because of the use of CO₂ as abrasive material. Additionally, there is no production of solid waste and gas emissions compared to the traditional abrasive methods, which include harmful metal particles. Nylon particles have poor performance. Thin aluminum or fiber hulls are also studied, with adequate performance for normal surfaces. Sand, the most used particle, performs adequate sweeping and penetration. But from the aspect of waste management, Fe and Cu particles are not suitable since they generate additional particles, and the same result occurs for sand particles, although sand waste can be handled in an environmental way in order to minimize waste [35].

2.5. Environmental Approaches and Considerations

The substitution of fossil oils (their drilling and processing in the well-established industry and production of synthetic industrial products) and waste recycling (prevention of waste accumulation and taking advantage of waste’s secondary uses) are providing the spark for environmental ideas related to producing renewable fuels with minimum greenhouse emissions as a substitute for fossil fuels. In the study by Jayakasan et al., the co-liquification of biomass is discussed, which comes from the tree Prosopis juliflora, and hydrocarbon-rich paint waste for “bio-oil” production is detailed. Paints, in general, are coatings that contain solid, liquid (emulsions, suspensions, etc.), and gaseous waste (hydrocarbons). Solid waste can be generated from solvent residues, blasting waste, or paint sludge. Co-liquefaction took place at varying biomass to paint-waste ratios (1:0, 0:1, 1:1, 2:1, and 1:2), at different temperatures from 340 to 440 °C, for a holding time of 60 min, with bentonite as a catalyst (1–5 wt.%). GC/MS and FT-IR analyses were carried out for “bio-oil” and the co-liquefaction aqueous phase. The “bio-oil” process yield was around 49.26 wt.% at 420 °C, 2:1 blend, and 4 wt.% of bentonite catalyst. Also, the presence of organic acids in the aqueous phase is shown. Finally, the energy and carbon recovery of “bio-oil” was around 70 wt.% and 96 wt.%, respectively [36].

The research by Madany et al. demonstrates that the Cu blasting grit waste-leaching tests, produced from shipbuilding and repair procedures in Bahrain, showed that the heavy hazardous metals tested (Cd, Zn, Cu, Pb, and Cr) were released in low concentrations, except for Cu and Zn. The leachability depends on pH values and the composition of the leaching medium. However, a continuous monitoring of leaching tests is suggested to avoid the opposite situation [37]. The work of Arevalo et al. involves studying the elimination of organotins in dockyard process waters through electrochemical treatment. The target is the reduction in organotins to very low concentration limits, with a desired range of 100 ng/L. The inorganic tin is considered harmless, and the organotins, such as tributyltin and dibutyltin, are found in the waters after the cleaning of the hulls of the vessels through blasting (25,000 ng/L of tributyltin as Sn and 5000 ng/L of dibutyltin), high-toxicity compounds. The combination of electrochemical treatment (with anodes Nb-coated with B-doped diamond and Ti-coated with IrO₂) with the activated carbon adsorption technique (eliminating both substances, Adsorbable Organic Halogens and residual oxidants) is necessary for lowering organotin levels. The levels must be lower, or bigger precautions are needed if the water is discharged in the aquatic environment [38].

In the study by Adeleye et al., the high environmental risk of antifouling means that paints releasing their biocides (Cu and Zn) into natural waters are analyzed as a substance of high concern for water toxicity. The study shows measurements of the release of various fractions of Cu (dissolved, nanosized, and bulk) from commercial Cu-based antifouling paint. Leaching tests took place for both dissolved and particulate copper compounds through XRD and XPS. Water salinity, a painted surface, and paint drying time are the main parameters that mainly influence the release of biocides [39]. Amara et al. have shown the effects of antifouling toxicity on several marine species with different biocides on algae, crustaceans, and fish. The ecological impacts on species and bioaccumulation constitute the main environmental impacts, with health risks, as the toxicity of copper and tributyltin is very high, although other biocides have better ecological properties, such as the current biocides (Irgarol 1051, Chlorothalonil, Dichlofluanid, Sea Nine 211, Zinc Pyrithione, and Diuron). It seems mandatory to develop environment-friendly non-stick coatings to prevent the adhesion of fouling organisms, and many formulations have been suggested, such as poly(ethylene oxide), acrylic resins, and silicones; for example, antifouling paints based on silicones (polydimethylsiloxane) have already been introduced in the international market for aquaculture and ships [40].

3. The Utilization of Grit Blasting Waste in Building Materials

Blasting waste is establishing a growing role in cement, concrete, and mortars. This waste can replace some of the natural sand, which lessens our dependence on new materials and helps the environment by reducing sand mining. Research indicates that using blasting waste can even boost the strength and reduce water absorption of these building materials. However, it is vital to thoroughly analyze the waste’s makeup and any potential impurities to guarantee the long-term performance and safety of the final construction. In the study of Yao et al., the researchers are preparing recycled-waste concrete powder and ground granulated blast-furnace slag as a way to decrease the high energy consumption and lower the carbon footprint. For this method involving wet foam, the discussion taking place involves the stability time of pre-formed foam, compressive strength, the dry density, the porosity and thermal conductivity of the specimen, the effects of alkali activator dosage, the dosage of CaCl₂⋅6H₂O, and foam content on the properties of foamed concrete (Figure 5). The compressive strength is decreased with the increase in alkali content. However, the porosity and dry density were less affected by the activator [41].

The purpose of the experiments of the research by Qomariah et al. is the exploitation of sandblasting waste in increasing the strength of mortar, concrete, and its absorption and mixing capacity. Sandblasting is widely available; hence, the utilization of this waste as an ingredient in concrete was investigated using different percentage substitutions of regular sand and using aggregate grading in accordance with Indonesian technical standards. The treatment age of different-day tests depends on the qualities of fresh concrete, consisting of concrete viscosity properties, such as specific gravity and compressive strength, using waste sand. With 30% sand replacement retrieved by sandblasting, specific gravity increases. From 7 to 14 days, specific gravity increased by 5.6%, and kept increasing up to 8.16% between 14 and 28 days. Specific gravity increases compared to concrete without waste sand were notable at 7 days, with 4.43% at 14 days, and 10.87% at 28 days, respectively. The sandblasting waste increases cement binding, and it is demonstrated that the compressive strength increased by 10.09% from 14 days to 28 days. XRF and SEM results show that the replacement of sandblasting waste content with sand applies to the utilization of waste in concrete, and its reuse as waste is can be developed as environmentally fine aggregate material [42].

Sabarinathan et al. deal with the reuse of alumina abrasive waste in concrete production. The alumina abrasive waste has the same function as sand, a fine aggregate of concrete. Several proportions of waste ABM have been tested as partial replacements of sand. Significant improvement was shown in the specimens regarding mechanical tests: flexural strength increases and tensile strength improvement are some of the mechanical properties of the concrete specimens. Water absorption and abrasive resistance have been increased significantly. Sustainability and waste management in the reuse of abrasive materials are very important in determining the impact of the cement industry on society [43].

On the other hand, Burande et al. extensively discussed the reuse of the paint sludge, i.e., the hazardous waste from the painting processes of the automotive industry. In order to avoid risky environmental processes such as incineration or combustion in industrial kilns, the addition of paint sludge in cement allows for the creation of concrete building materials without downgrading the prime properties of the final products. It contributes to environmental protection without generating emissions, combining a “cost-effective” procedure, as it involves no recycling of the paint sludge (high solvent percentage, high solids, etc.) [44]. In the study by Lermen et al., the attenuation of X-ray radiation while using shield products is investigated. Those products come from mixing sandblasting waste with cement materials as mortars. The natural sand is replaced successfully by sandblasting waste, which is composed of steel (steel shot) [45]. In the paper by Borucka-Lipska et al., sandblasting grit, generated from the cleaning of steel structures such as bridges and metal structures (warehouses), is used in cement mortars. The study focuses on rheological properties and strength properties. The technical result is that the higher the amount of contaminated grit that is added, the lower the benefit of tensile strength in the end product. The flow ability and the compressive strength of the cement mortars are decreased (low thixotropy), but it comes with the advantage of less waste disposal [46].

The research by Tajunnisa et al. focuses on using high-calcium fly ash from Indonesia’s Paiton power plant—a plentiful waste product—to create more environmentally friendly concrete. The goal is to add valuable data to the growing research on sustainable concrete alternatives. In addition, the use of abundant waste material in Indonesia, namely class C fly ash (FA), is also studied by making cubic mortar specimens. Sandblasting waste, a material in abundance, is substituted for class C fly ash, lengthening the hardening time of the paste. Also, the addition of sandblasting waste eventually has a negative effect because it reduces the compressive strength of mortar specimens. Sandblasting substitution improves the workability of the geopolymer because of the high Si content in sandblasting. A “Geopolymer” is often referred to as a mineral structure with semi-crystalline networks, created by successive condensations. The combination of waste sandblasting and class C fly ash shows better performance on geopolymer mortars. The addition of sandblasting waste is one of the solutions to the problem of the setting time of ABM made from class C fly ash, which has a fast set time. The plan for future research is to estimate the optimal percentage when replacing sandblasting waste with class C fly ash, to ensure better mechanical properties of alkali-activated concrete [47].

In an earlier study by Qomariah et al., the addition of sandblasting waste in terms of mortar strength, concrete strength, absorption, and workability of the mix is demonstrated. The experiment uses mortar cube and cylindrical concrete tests and relevant curing time intervals of 3 and 7 days for mortar, and 7 and 28 days for concrete (ASTM C-150 for mortar and SNI-03-2834-2000 for concrete). The percentages of waste sand are 0 wt.%, 10 wt.%, 20 wt.%, and 30 wt.% of natural sand. The evaluation of waste sand was driven by the strength of mortar, which increased as the fraction of waste sand increased. For the concrete mix, the mix became workable when increasing the slump value. For the strength of concrete, it increased as a function of substituting natural sand to waste sand, although the level of fresh concrete increased [48].

The behavior of concrete produced by combined foundry sand/recycled fine aggregate and fly ash/ground granulated blast slag is presented in the paper by Gholampour et al. Fly ash (FA) and ground granulated blast-furnace slag, as cement replacement materials, and foundry sand and recycled fine aggregate, as sand replacement materials, have been demonstrated to be eco-friendly construction materials. In that way, decreasing the impact of concrete and construction waste on the environment for sustainability and cleaner production in the construction industry is inevitable. The tests evaluate compressive strength, water absorption, tensile strength, and flexural strength. As described in the paper, there are very promising mechanical results combined with the reduced environmental impact [49].

In the paper by Sukmana et al., they suggest using silica sand from sandblasting waste as a type of cellular lightweight concrete. The experiments are designed to find out the factors that mainly affect the compressive strength of lightweight concrete and, furthermore, to find the optimum composition of lightweight concrete with maximum compressive strength. The results show that Portland cement and the ratio of paste/foam in it have a significant effect on the compressive strength of cellular lightweight concrete using silica sand from sandblasting waste. The best composition of cellular lightweight concrete in these experiments was 40 wt.% Portland cement, 40 wt.% silica sand, and 0.6 paste/foam. Thus, the results are very promising for this application [50].

In the article by Suaiam et al., the properties of self-consolidating concrete are presented, to which a high volume of fly-ash waste (FA) and recycled alumina waste (AW) were added. FA was used as a cement substitution at 40 wt.% and 60 wt.%, and AW was used as a substitute for the fine aggregate at 25 wt.%, 50 wt.%, 75 wt.%, and 100 wt.%. The research focuses on two main factors: the workability and mechanical properties of the blends. The analysis methods involve evaluating slump flow, J-ring flow behavior, blocking flow evaluation, V-funnel, compressive strength, and ultrasonic pulse velocity. The results showed that the self-consolidating concrete blends that included AW required increased doses of “plasticizer” and produced denser fresh concrete. With the increased cement content and different FA content, and the percentage of “plasticizer” required, the thickness of the fresh self-consolidating concrete finally decreased. When AW was incorporated at between 25 wt.% and 75 wt.%, its rheological and mechanical benefits became significant enough that including it in self-consolidating concrete became practical. It is suggested that the manufacturing of self-consolidating concrete blends using high volumes of FA and AW, materials with environmental attributes characteristic of the “green” materials described previously, may replace river sand (decrease natural sourcing) and, of course, ensure sustainable concrete production [51].

In the paper by Avci et al., the recycling of hazardous toxic waste of paint sludge is studied as a form of aggregate replacement for sand additions in cement and lime. The results from paint sludge/cement and paint sludge/lime specimens show that changes took place in mechanical properties because of the existing spots and expansion. The addition of paint sludge increased the expansion and porous structure for the composite specimens (thermal and sound insulation properties). On the other hand, flexural and compressive strength were decreased with the increase in paint-sludge content. Finally, the addition of sludge to the mortars increased water absorption. Recycled paint sludge in mortar specimens made of Portland cement creates potential for lightweight residential construction materials. The material possesses economic value in certain applications, and at the same time there is a serious decrease in the land disposal of hazardous paint-waste sludge [52]. In the paper by Song et al., they examine the handling of the total waste (surface antifouling waste, paints, sandblasting waste, water from hull cleaning) from a shipyard. Tributyltin, the main organotin compound, can be efficiently removed from the sandblasting waste with heat treatment at 1000 °C for at least 1 h. The heat treatment detoxifies the sandblasting waste, and the residual can be reused safely for land reclamation or for construction of building materials [30].

4. The Utilization of Grit Blasting Waste in Asphalt Mixes/Road Construction

Blasting waste offers a sustainable alternative in asphalt mixes and road construction. It can serve as a partial replacement for natural aggregates, reducing the demand for virgin materials and minimizing landfill waste. Incorporating this waste can even enhance certain properties of asphalt, like skid resistance and durability, while also potentially lowering construction costs. However, thorough testing is essential to ensure the waste material’s consistent quality and to prevent any long-term environmental or performance issues. In the paper by Mokhtar et al., the reuse of sandblasting waste in road construction is investigated. Several blasting waste (wt.%) concentrations were tested in bitumen mixtures. The specimen with 10 wt.% addition of sandblasting was especially successful, with significant stability and bulk density values. There is potential for when mixing abrasive lasting material with bitumen for pavement applications, because it is the most efficient compared to other mixing compounds with bitumen [53].

The paper by Buruiana et al. deals with the use of sandblasting grit in asphalt mixtures. The size of the granules of sandblasting grit is the analyzed parameter. It is shown that there is a strong feasibility of replacement of crushed sand by sandblasting grit with an improvement of the wear and the tear strength of the pavement [54]. In the study by Taha et al., the recycling of paint grit into asphalt mixtures and cement mortars is tested. The high content of hazardous metals in the paint grit, such as Pb, Cd, and Cr (VI), is the main environmental concern, placing a focus on avoiding waste disposal and protecting water sources. In the Portland cement mortar, it is shown that there is a small increase in compressive strength, especially when the mixture has 10 wt.% sand with 90 wt.% paint grit. In the asphalt concrete mixture, it is shown that there is a skid resistance very similar to both mixtures, either the control mix or paint-contaminated grit. From an environmental perspective, it is quite positive [55].

In the paper by Ahmedzade et al., the reuse of steel slag (blasting waste, furnace slag, scrap metal) as a coarse aggregate in hot-mix asphalt was explored. Different asphalt mixtures were tested mainly for their mechanical properties. The reuse of steel slag is important because there is an improvement in the mechanical properties of the asphalt mixtures, such as tensile strength, stiffness, and creep. Also, the electrical conductivity of the mixture is high enough so that the hot-mix asphalt can be used for de-icing the pavements of parking areas, as well as highway bridges, where thermo-electrical properties are needed. In conclusion, the steel-slag mixtures seem to be better overall compared to relevant limestone mixtures [56].

In the work by Zanetti et al., the production of pavement products through bituminous binders is presented, where paint sludge is added. It explores a patent of the modified binders with the use of paint sludge, coming from the automotive industries. The physical characteristics, viscosity, and storage stability of sludge-modified binders are evaluated. The evaluation focuses on environmental impacts (paint sludge has a high content of heavy metals such as Cr, Mn, Zn, and Co). It seems that this application is better than incineration and landfill as an option for the reuse of paint sludge, because the leaching tests demonstrate that the heavy metals can be restrained inside the matrix of bituminous pavement compounds [57].

The paper by Al-Sayed et al. involves the Arab Shipbuilding and Repair Yard Company in Bahrain, where a large amount of solid waste is generated every year (approximately 6000 Mt). The waste is spent Cu grit used for sandblasting in the cleaning operations of tankers in the dockyard. The recycling of the waste as a fine aggregate in the road construction industry is the focus of the study. There are five different grits and ratios in mixtures with asphalt. Several parameters are investigated, such as Marshall methods like stability, flow, Marshall quotient (kN mm⁻¹), voids in the mix (%), voids in the mineral aggregate (%), and the voids filled with bitumen (%). The results confirmed that copper grit waste can be utilized as a substitute for normal sand as a fine aggregate in asphaltic concrete wearing courses [58].

The paper by Vishnu et al. describes the ways to reuse the waste formed (urban and semi-urban) in the construction of bituminous pavements. The waste materials are many and with different compositions: scrap tires, plastic waste, glass, coal waste, fly ash, concrete waste, wood waste, etc. Bituminous pavement construction is an option avoiding incineration, landfills or ground disposal, or discharge to sewers or rivers. This work evaluates the various applications of solid waste in sustainable pavement engineering and enhances the reutilization of solid waste as road construction material. Life-cycle assessment (LCA) is the tool used for the evaluation of the environmental impact of solid waste as a construction material. In construction materials, the waste will take the form of aggregates, reinforcement fibers, fillers, additives, etc. The environmental effects are lower energy consumption, reduced pollution, and increased recycling and reuse [59].

The paper by Means et al. presents the options of recycling the spent sandblasting grit into asphalt concrete and the upcoming technical issues as an alternative solution instead of landfill disposal. The chemical characterization of spent ABM, the asphalt mix design, the results of tests, the regulatory compliance, and a discussion of the advantages and disadvantages of recycling spent ABM into asphalt concrete are the main topics. There are many different types of sandblasting grit, such as Ni smelting slag, Cu smelting slag, natural sand, and steel shot. The test results show that high-quality asphalt concrete products can be produced at a spent ABM proportion of about 7–10 wt.% by weight. Similar results provided from another study, for a different group of spent ABM, demonstrated acceptable-quality asphalt concrete at a mixing percentage of ABM of 10–20 wt.% by weight. From the economic aspect, the cost of recycling ABM into asphalt concrete is much lower than the cost of disposal, so, the recycling and reuse option is the priority for hazardous waste management [60].

In the paper by Lopez-Alonso et al., the reuse of recycled materials in road constructions and in civil constructions is studied. Several studies have introduced recycled aggregates with appropriate results, either recycled concrete aggregates or mixed recycled aggregates. Both have lower density, higher water absorption, and lower mechanical strength than natural aggregates. Another option is the mixing of AW, generated from aluminum refinement, with RA in order to improve compaction and bearing capacity. The laboratory results of different mixing ratios with different combinations of all these materials compare the mechanical behaviors and microstructural properties of the mixtures, where it is shown that there is a significant increase in the compressive strength and the formation of new hydrated particles in cement, respectively. The conclusion is that the use of AW as an aggregate mixed with concrete recycled aggregates and mixed recycled aggregates in road construction is a valuable recycling option [61].

The work of Ruffino et al. involves deeply analyzing the financial costs in Italy and the environmental impacts related to the recycling process of paint sludge for the first time, through the lens of the spray application of paints in the automotive industry, as a modifier agent in bituminous binders used in hot-mixture asphalts for pavements (Figure 6). Previously, it was shown that the substitution of bitumen with up to 20 wt.% of PS in the hot-mixture asphalt binder was acceptable when considering the technical aspects of the pavement and did not create any environmental problem in the soil and water. The annual production of paint sludge from Italian automotive plants (3 ktpa) could correspond to 1.64 km² of asphalt pavements (with an average road width of 5 m), which totals approximately 330 km. Drying and milling are required and must be carried out, but even with these treatments, we avoid incineration or disposal in a landfill for hazardous waste. The LCA analysis demonstrated that the reuse of paint sludge is a very promising eco-friendly method for paint-sludge waste management [62].

The study by Buruiana et al. described research on recycling and reusing two types of waste that contribute to pollution, namely plastic polypropylene and abrasive blasting grit waste, in asphalt roads. The tests include the wear-layer performance of the road, stability under different temperatures, flow rate, solid–liquid reports before and after freezing, apparent density, and water absorption. The composition was analyzed by SEM. In order to make an asphalt mixture for the wear layer in road construction, the mixture contains aggregates, filler, bitumens, abrasive blasting grit waste, and polypropylene. In the formulation, there were three different additions of PP: 0.1 wt.%, 0.3 wt.%, and 0.6 wt.%. An improvement in the mixture performance is shown with the asphalt mixture sample with 0.3 wt.% of PP, also avoiding cracking because of sudden temperature changes. Τhe use of recycled plastics in asphalt binders and mixtures is a well-known issue in many previous studies. Ahmed et al. studied the LDPE and HDPE for asphalt modification through a wet process. It was recommended that a dosage of 2 wt.% of LDPE and HDPE in asphalt binder be used, and the results were better for the HDPE mixture than the LDPE mixture. Appiah et al. evaluated the use of recycled HDPE and PP for asphalt modification through a wet process. The best dosage taken from the experiments was 2 wt.% HDPE and 3 wt.% PP by determining the weight of the asphalt binder. There was an increase in both the softening point and viscosity of the base binder through the addition of HDPE and PP in the asphalt mixture. Plastic, microplastics, sandblasting grit, and hazardous waste are all materials with high environmental risk, so the combined recyclability suggests a sustainable solution [63,64].

The research presented at the Geoconference in 2008 by Mattei et al. concerns the reuse of the spent abrasive blasting material (ABM, coming from two New Orleans shipyards) in a modified hot-mix asphalt, replacing part of the fine aggregates. The experiments demonstrated that hot-mix asphalt modified with 5–7 wt.% coal slag ABM or 10 wt.% silica sand ABM could be an acceptable mixture. Also, the leaching tests provided a very encouraging result from an environmental perspective, because the levels of hazardous metal concentrations are well below those stipulated by the regulations. It is concluded that the reuse of the two spent ABMs tested in this study as part of hot-mix asphalt is feasible in the New Orleans area. This recycling option is a very promising waste management solution [65].

5. The Utilization of Grit Blasting Waste in Ceramics and Composite Materials

The incorporation of blasting waste into ceramics can enhance mechanical properties and reduce raw material costs, while in composite materials, it can serve as a reinforcing filler, contributing to improved strength and durability. This repurposing not only offers economic benefits but also addresses environmental concerns by diverting waste from landfills and promoting a circular economy. In the work of Karlsson et al., the pyrolysis of a model paint containing several types of inorganic pigments in a microwave-heated unit is studied. The purpose of the pyrolysis process was the recovery and the recycling of inorganic components in the paint, mostly TiO₂. The simulated waste paint was based on a common formulation including TiO₂ (rutile form) together with dolomite, kaolin, mica, and talc. TGA experiments showed that a pyrolysis process at temperatures below 500 °C leaves the crystal structure of the pigments/fillers intact, but the organic binder is decomposed. The pyrolyzed paint residue was too dark. Tests with heat-treated pyrolysis residues in paint formulations as pigment replacements show a significant decrease in paint whiteness, but the opacity, gloss, and durability were almost at the same level as standard paint. The dispersibility of the recycled mix of pigments and extenders in the paint was inadequate. The recycled material showed very good results for future uses as a pigment/extender, but further evaluation is needed to optimize the recycled product to meet whiteness and dispersion requirements in order to be incorporated in paint formulations effectively [66].

Although TiO₂ is the major white pigment used by the paint industry, its production requires high energy consumption (high carbon footprint), so its recovery from waste paint is an appealing option. In this paper, Karlsson et al. describe the recovery of rutile pigments through a thermal recycling process (pyrolysis, oxidation, and washing). The pigments were analyzed through XRD, XPS, BET, laser diffraction for particle-size analysis, and zeta-potential measurements before and after the recycling process. It was shown that the rutile cores did not demonstrate large changes in particle-size distribution and surface charge, but the XPS and zeta-potential measurements that were carried out showed that the surface coating of the pigments had a high level of degradation. If the recycled pigment had a good quality profile and prolonged life, the replacement of virgin pigments in new paint formulations would be a very promising option, for example, to be added in interior paint formulations. If not, another application with less important pigments is an option. In general, sustainable product development is the main issue hindering successful recycling and reduction in waste [67].

The study by Suchanek et al. deals with the converting of paint sludge, generated in the automotive industry, into composite ceramic products. Pyrolysis is the method of conversion. There are three tested composite compounds, used as reinforcing materials, containing CaTiO₃, BaTiO₃, TiO₂, Al₂O₃, etc., at different sintering temperatures. Metal-matrix composites and those reinforced with PP compounds are the main final applications of this ceramic composition [68]. The study by Brabrand et al. deals with the use of abrasive blasting waste, generated from metal bridge maintenance, in non-concrete structures (riprap and Portland cement mixtures). It involves an examination of different extracts of hazardous metals such as Cd, Cr, and Pb. Also, they study different percentages of spent sandblasting grit added in the cement mixture (replacing 100 wt.% clean sand) and compare the compressive strength, which is increased. Finally, when adding spent abrasive dust, up to at least 25 wt.%, the compressive strength is increased as well [69].

In the paper by Mymrin et al., the recycling of mixed industrial metallurgical waste into ceramic materials (bricks) is studied. The industrial hazardous waste has a high content of heavy metals, such as Pb, Sr, and Cr. In order to reduce waste disposal, they focus on the development of eco-friendly construction products. It seems that this has a positive environmental impact, because the leaching and the solubility tests of the final products show encouraging results, although the hazardous content of the waste is high. Glassy structures in the bricks are studied through EDS, XRD, and SEM analysis [70].

In the work of Wang et al., they detail the addition of abrasive AW in different percentages during the production of fireclay bricks under different firing temperatures. The mechanical properties, such as compressive and bending strengths, and the physical properties, such as shrinkage and porosity, are estimated, and in general, the higher the concentration of abrasive alumina, the better the result. It seems that the refractory properties of the bricks are slightly improved. The economic benefit of the use of abrasive alumina and the waste utilization are the main topics. The conversion of non-degradable industrial waste, into abrasive alumina, is recommended [71].

The study by Palaniyappan et al. explores the impact of incorporating alumina abrasive waste into the production of fireclay bricks. Samples containing 0 wt.%, 10 wt.%, 20 wt.%, and 30 wt.% waste were prepared, pressed at 150 MPa, and fired at 900 °C and 1100 °C. Key properties—including bulk density, apparent porosity, linear shrinkage, and water absorption—were evaluated. The results revealed that the sample with 30 wt.% waste (BFC30) exhibited notable improvements in strength and bulk density. Specifically, BFC30 reached a maximum compressive strength of 31.15 MPa, with reduced water absorption (5.84%) and linear shrinkage (1.64%). It also achieved the highest bending strength at 35.34 MPa. Increasing the waste content enhanced the mechanical properties of the bricks, attributed to the higher alumina and silica content introduced by the waste. BFC30 also showed the best wear resistance, recording the lowest volumetric wear rate (2.4 g/mm³) at a 30° impingement angle. Overall, substituting raw materials with alumina abrasive waste not only enhances the refractory performance of fireclay bricks but also promotes sustainable waste reuse and cost efficiency in manufacturing (Figure 7) [72]. In the work of Batista Marin et al., dealing with the recycling of byproducts from the steel-manufacturing process, they determine whether mill scale, a pure waste product, could be used as a pigment for clay-fired bricks. Although the flexural modulus and the compressive strength of the clay slightly decrease, it is the only way to incorporate an industrial byproduct into a productive cycle without spending a renewable source to produce natural clay. The porosity of the clay-fired brick increases a little (4%), and it is important that there is no chemical reaction between mill scale and clay [73].

An alternative solution for handling the significant waste amounts of foundries is explored in the study by Rodriguez et al. Reuse and recycling are the primary objectives, in order to minimize waste disposal and recover materials and energy. The reuse solution studied is the addition of foundry waste into ceramic-matrix composites. Two types of residues were used to produce the composites, green sand and grit blasting powder, in formulations with concentrations of 5–10 wt.%. Uniaxial molding pressing and a thermal treatment at 1000 °C are the key steps to produce the specimen. The materials were characterized by XRF, XRD, particle-size determination, linear retraction, water absorption, mechanical strength, leaching, and solubilization. The incorporation of waste into the ceramic matrix improves the processing of the products, and the mechanical properties are quite promising for industrial-scale production. The mechanical properties studied are strength and water absorption. From the perspective of evaluating the hazards of the produced samples, leaching and solubilization classified the waste as not immobilized in the ceramic structure [74].

As the blasting removes large amounts of many different materials from every surface we clean, glass is one of the sandblasting materials that is removed after the process. In this study by Pinter et al., the method of recycling and reusing glass is investigated. In cement production, which is suggested first, glass can be mixed with it and the strength of large concrete bodies can be increased. The second suggestion is a technology called “Geofil Bubbles,” which is a glass-based expanded gravel (bead) additive from recycled waste, where the glass waste is collected from civil and municipal waste management systems most of the time [75].

Lightweight products are a global need for many applications, and the introduction of composite materials is necessary; for example, aluminum with thermoplastic polymers is a very widely used composite. Adhesive bonding makes an important contribution in joining dissimilar materials, but surface preparation is necessary for achieving good results. In the study by Ramaswany et al., alumina grit blasting is investigated as a surface-preparation grit blasting material for thermoplastic-matrix composites to be bonded to aluminum alloys. Grit blasting is performed for many varied durations of time. All modifications of the matter are analyzed using goniometry, profilometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The bonding joints are tested at quasi-static and dynamic loading rates using fractography analysis. Grit blasting can thus be a simple yet effective surface-preparation technique for composites to be bonded to aluminum. Grit blasting is the pretreatment for bonding a carbon-fiber thermoplastic composite to aluminum joints, which is tested and evaluated. The treated surfaces have been studied using many different surface-chemistry and topography characterization analyses. The alumina grit blasting has good performance as a surface treatment for carbon fiber with polyamide 12 composite. Fast robotic manufacturing has the ability to use this material for this procedure, a low-cost option, with successful repeatability and productive bonding of several types of joints in automotive structures [76].

In the research by Lin et al., they concentrate on recycling and the reuse of sandblasting waste, which consists of SiO₂ and Al₂O₃ and is generated from the surface-treatment process of solar cells, in order to replace waste diatomite (replacement percentage up to 20 wt.%) for the manufacturing of porous ceramics capable of water retention. Heating temperatures for the manufacturing of the sintered products, thermal conductivity, and compressive strength are the factors that are analyzed through FTIR and MIP instruments for the measurement of porosity (pore size and volume) and water absorption. Waste diatomite and sandblasting waste are particularly apt in the replacement of porous ceramic material with appropriate mechanical properties [77].

In the study by Ho et al., the feasibility of reusing waste diatomite and sandblasting waste (generated from the surface treatment process in the solar industry) to produce water-retaining porous ceramic is demonstrated. Sandblasting waste mainly contains Al₂O₃ and very small percentages of silicon (SiO₂) and silicon carbide (SiC). The structure of waste diatomite is the crystal cristobalite. The structure of the produced samples was analyzed for water absorption, water retention in different temperatures, and compressive strength through XRD and SEM. The results show that the water absorption of the water-retaining porous ceramic samples decreased significantly as the replacement rate of sandblasting waste increased. When the heating temperatures were 1200 °C and 1270 °C and water-retaining porous ceramic samples contained 15–20 wt.% sandblasting waste, the water absorption of the water-retaining porous ceramic samples decreased considerably, and the compressive strength of the samples was significantly greater than that of those with no sandblasting waste. The sample ceramics change with the incorporation of sandblasting waste and waste diatomite and are related to firing temperatures, compressive strength, and water absorption. The water-retaining porous ceramic samples have potential as water-retaining materials [78].

The study by Meneghel et al. investigates technical suggestions for the reuse of carbon-steel shot blast waste to produce solid products and sintered bodies, using powder metallurgy. The principal contribution of the study is that the method facilitates the creation of a powder mixture with the highest density from a non-commercial powder. Density, sintering time, the particle-size variation in the blasting waste with its oxidized layer, the flow rate and apparent density of the blasting waste, the microstructure of the sintered bodies, and their hardness are the parameters studied and analyzed in the study. The method has an overall positive performance, with the reuse of blasting waste, an economical raw material, but a deeper analysis of the mechanical properties of the sintered bodies is necessary, such as the tensile strength, elongation, and fatigue limit of the sintered bodies. The sintered bodies showed promising properties, and the powder metallurgy method for recycling shot blast waste is considered a feasible method [79]. The study by Oranli et al. involved the modification of the surface functionality and aesthetics of polymeric materials by sandblasting treatment. The development of a numerical model is studied to predict the change in the surface morphology of the polymer. The blasting parameters are the shot size and shape variations in blasting media. The experiments are performed using polycarbonate as the substrate material and alumina as the blasting media. Polycarbonate is selected as the polymeric material due to its relatively low cost, high stiffness, and ultimate tensile strength, and its availability compared to other thermoplastic polymers. The blasting media, alumina, is chosen due to its high hardness, excellent recyclability, cost-effectiveness, and its wide application in sandblasting of polymers [80].

The study by Lin et al. suggests the production of a zeolite humidity-control material via alkaline melting and hydrothermal synthesis with a specific formula based on solar-panel waste glass and sandblasting waste. There are assessments for Si/Al molar ratio, crystallization temperature, and crystallization time on microstructure and humidity-control properties. This study provides a feasible alternative use for recycled solar-panel waste glass and sandblasting waste. XRD analysis confirms that the fabricated zeolite material had no characteristic peaks of waste sandblasting and solar-panel waste glass, which was evidenced by the high purity of the zeolite crystallinity, reaching 82.41%. This study explores the unique properties of synthetic hydrophilic zeolite humidity-controlling materials but also provides a feasible possibility of reuse and in-line production of LCD waste glass and waste sandblasting production resources, solving waste disposal problems [81].

The study by Rozhkovskaya et al. provides a solution for the recycling of alum sludge with either lithium slag or bottle glass to make high-purity zeolite LTA beads. The synthesis approach involved the fusion of the waste material with sodium hydroxide, with hydrothermal crystallization at the end. The purity of zeolite LTA was between 80 and 85 wt.% from the two waste combinations, which is a significant percentage. The importance of this finding is high, because zeolite powder is made from waste materials, but further analysis is also needed for the production of shaped forms. The production of extrudates or beads, commercially used forms, is a promising aspect of the paper. The commercial zeolite synthesis must be evaluated economically as far as the reuse of waste products is concerned, but the two fusion stages have a high cost [82].

6. The Utilization of Grit Blasting Waste in Land Recovery

Blasting waste in landfills is mainly used as a disposal method, typically considered a last resort in waste management. While some non-hazardous blasting waste can go directly into a landfill, it is vital to test it rigorously first to confirm it is safe. This is because blasting waste, especially that obtained from removing old paint or coatings, might contain heavy metals or other toxic substances. Such materials require specialized hazardous waste landfills or treatment to prevent contaminating soil and water. Ultimately, the aim is to send as little blasting waste to landfills as possible due to the environmental impact and high disposal costs, instead encouraging more sustainable options like recycling and reuse in other materials. In the paper by Lim et al., they studied land recovery using spent copper slag. This waste has been tested for shear strength and hydraulic conductivity of the landfill. Also, the study provides more information for the leaching of heavy metals (to the landfill) in order to ensure (pH of land to measurement, redox measurement) the safe disposal of the waste to the land without facing toxicity impacts [83].

The study by Nikolic et al. deals with the immobilization of used sandblasting grit in a geopolymer that contains fly ash. It is shown that the compressive strength of the geopolymer with fly ash, using sandblasting grit, is reduced compared to the compressive strength of fly-ash-based geopolymer [84]. The study by Prasad et al. shows that Cu slag can be used as a structural filling material for mechanically stabilized earth walls and reinforced soil structures in place of conventional fill materials. Cu slag contains iron silicates, calcium oxide, and alumina, with small amounts of Cu, Pb, Zn, and other metals. The gradation, physical, shear strength characteristics, and electrochemical properties of copper slag follow the specifications for a filler recommended for use in mechanically stabilized earth walls and reinforced soil structures. Physical–chemical and electrochemical characterizations are carried out to find out the feasibility of Cu slag as a structural filler for mechanically stabilized earth walls and reinforced soil slopes. The geogrid that incorporates Cu slag provides a better soil–geosynthetic interface apparent coefficient of friction compared to the reported values in the literature. The results of pullout tests with geogrids incorporated in Cu slag show that Cu slag has a high dynamic for use as a structural fill material in place of conventional fill material for reinforced soil structures [85].

Song et al. conducted a study based on the treatment of antifouling paint waste generated at shipyards, including sandblast waste and ship hull-washing wastewater. The sandblast waste was effectively detoxified through heat treatment, with the efficiency influenced by both the heating temperature and the duration of treatment. At 1000 °C and a treatment time of 1 h, over 99 wt.% of the total organotin compounds were removed from the sandblast waste. For the treatment of ship hull-washing wastewater, solvent extraction was applied (Figure 8). Ship diesel proved to be an effective solvent for extracting tributyltin (TBT), with an optimal volume of approximately 10 mL per 1 L of wastewater. The efficiency of TBT extraction was strongly dependent on the agitation intensity. Sandblast waste was effectively detoxified through heat treatment, with efficiency influenced by both the treatment temperature and duration. At 1000 °C for 1 h, over 99 wt.% of the organotin compounds were removed. The tin-free sand produced through this process has potential for reuse as construction material or as cover soil for landfill applications [30].

7. Conclusions

The paper reviews the materials and methods applied to the marine repair industry in order to remove the rust, the sea deposits (salt and algae), coatings like paint, and antifouling agents that remain on the metallic surface of the ships, as well as what lies under the water. The extent of these applications is vast, especially in countries with severe shipping, economy, trade, and transportation domains. The effective removal of the deposits is crucial for the longevity of the ship and its maintenance, which is cost-depriving for the owners, then the clients, and eventually the states. The next issue that arises is the management of the waste produced from the ship-repair practices, which include the grit materials, the paint sludge, the mineral deposits, and others. Those blends, mostly of an inorganic nature, may find reusage applications in road construction materials as asphalt ingredients, in building construction materials as cement ingredients, in composites as ceramics replacements, and in insulation applications as well. In this way, the substantial quantities of natural resources applied as abrasive grits (usually oxides, sand, minerals, metals or steel), the water used in the blast process, and the high amounts of energy would not be totally wasted.