Search Results (18)

The escalating global demand for fresh water, driven by urbanization and industrial growth, underscores the need for sustainable water management, particularly in the water-intensive construction sector. Although prior studies have primarily concentrated on treated wastewater, the practical viability of utilizing untreated wastewater has not been thoroughly investigated—especially in developing nations where treatment expenses frequently impede actual implementation, even for non-structural uses. While prior research has focused on treated wastewater, the potential of untreated or partially treated wastewater from diverse industrial sources remains underexplored. This study investigates the feasibility of incorporating wastewater from textile, sugar mill, service station, sewage, and fertilizer industries into concrete paver block production. The novelty lies in a dual approach, combining experimental analysis with XGBoost-based machine learning (ML) models to predict the impact of key physicochemical parameters—such as Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Hardness—on mechanical properties like compressive strength (CS), water absorption (WA), ultrasonic pulse velocity (UPV), and dynamic modulus of elasticity (DME). The ML models showed high predictive accuracy for CS (R² = 0.92) and UPV (R² = 0.97 direct, 0.99 indirect), aligning closely with experimental data. Notably, concrete pavers produced with textile (CP-TXW) and sugar mill wastewater (CP-SUW) attained 28-day compressive strengths of 47.95 MPa and exceeding 48 MPa, respectively, conforming to ASTM C936 standards and demonstrating the potential to substitute fresh water for non-structural applications. These findings demonstrate the viability of using untreated wastewater in concrete production with minimal treatment, offering a cost-effective, sustainable solution that reduces fresh water dependency while supporting environmentally responsible construction practices aligned with SDG 6 (Clean Water and Sanitation) and SDG 12 (Responsible Consumption and Production). Additionally, the model serves as a practical screening tool for identifying and prioritizing viable wastewater sources in concrete production, complementing mandatory laboratory testing in industrial applications. Full article

This research aimed to investigate the potential of using alkali activation technology to valorize steel slag and bauxite residue for the production of high-performance pavement blocks. By utilizing these industrial by-products, the study seeks to reduce their environmental impact and support the development of sustainable construction materials. Lab-scale testing showed that bauxite pavers showed a decrease in mechanical strength with increasing replacement of ordinary Portland cement. Partial replacement up to 20% still exceeded 30 MPa in compressive strength. Steel slag-based pavers achieved the 30 MPa threshold required for the application with selected mix designs. Pilot-scale production-optimized formulations and standards testing, including freeze–thaw resistance, confirmed the technical viability of these products. Life cycle analysis indicated a 25–27% reduction in CO₂ emissions for slag-based tiles compared to traditional concrete tiles. Moreover, using industrial residue reduced mineral resource depletion. This study examined the properties of the resulting alkali-activated binders, their ecological benefits, and their performance compared to conventional materials. Through a comprehensive analysis of these applications, our research promotes the circular economy and the advancement of sustainable construction products. Full article

The concrete block pavement (CBP) system has a surface layer consisting of concrete block pavers and joint sand over a bedding sand layer. The non-homogeneous nature of the surface course of CBP, along with different laying patterns and shapes of block pavers, makes the analysis of CBP cumbersome. In this study, the surface course of CBP was modeled based on the slab action of the block pavers and joint sand, which are connected together in full contact. Four different laying patterns, including herringbone, stretcher, parquet, and square, were modeled using a finite element model. The elastic moduli of the block pavers varied from 2500 MPa to 45,000 MPa, with thicknesses ranging from 60 mm to 120 mm. As a result, modeling of CBP based on slab action can be considered a realistic strategy. In addition, a dataset was created based on quantitative inputs, e.g., elastic modulus and thickness of the block pavers, and qualitative input, i.e., block laying patterns. The approaches of machine learning adopted were support vector regression, Gaussian process regression, single-layer and deep artificial neural networks, and least squares boosting to implement prediction approach based on input and output. The analyses of statistical accuracy of all five machine learning methods showed high accuracy; however, the Gaussian process and deep artificial neural network methods resulted in the most accurate outputs and are recommended for further studies. Based on the machine learning models, digitalization is achieved through the development of simple, user-friendly software for electronic devices in order to perform a preliminary analysis of different laying patterns of CBP. Such a platform may result in less laboratory work and boosts the level of sustainability in concrete block pavement technology. Full article

This study aimed to validate that laboratory-scale results could be commercially replicated when manufacturing marketable precast concrete. Construction and demolition waste (CDW) was separated into two (fine and coarse) recycled aggregates (RAs). Precast paver and kerb units were fabricated by partial or total substitution of natural aggregates (NAs) by RAs. The study involved the comprehensive characterisation of raw materials, including particle size distribution, mineral composition, and elemental composition. Paver blocks and kerbs manufactured with up to 50% RAs showed mechanical resistance (T = 3.7 ± 0.2 and B = 5.3 ± 0.6 MPa, respectively), water absorption between 5.3–5.7%, and abrasion resistance (approximately 20.2 mm), which met the standard requirements (UNE-EN 1340:2004 and UNE-EN 1338:2004). Furthermore, industrial-scale precast pavement units demonstrated strength and durability suitable for heavy traffic areas. A reduction of 13% in cement content could maintain the requirements with a partial RA substitution of 25%, offering economic and environmental benefits. Therefore, it is feasible at an industrial level to replace NAs with RAs, promoting durability and technological properties with a positive environmental impact and considerably reducing CO₂ emissions by up to 65%. Overall, pavers with RAs manufactured at the laboratory scale met mechanical standards, and the kerb stones showed improvements in abrasion resistance. On an industrial scale, kerb stones and precast blocks with specific substitutions can meet strength, water absorption, and abrasion requirements, allowing a reduction in cement content. Full article

Dry concrete is a kind of concrete whose fresh mixture has almost no flowability and is widely used in the production of small-size unreinforced compression-compacted concrete blocks in plants. Considering the shortage of natural river sand and freshwater for concrete production, this study proposes that sea sand and seawater can be directly used in the manufacture of compression-compacted dry concrete paver blocks. The idea was verified in the laboratory to find suitable mix proportions and forming pressure, which are two key parameters for the production of paver blocks. Furthermore, the effect of sea sand replacement ratio and seawater replacement ratio is investigated, where compression and flexural tensile tests were conducted on lab-made paver blocks at different ages. The experimental results reveal that both the compressive and flexural tensile strengths of paver blocks increased when sea sand and seawater were adopted. It is finally suggested that sea sand and seawater are suitable for the production of unreinforced paver blocks with enhanced mechanical performance. Full article

India is confronted with the substantial issue of plastic debris due to the absence of an efficient waste management infrastructure. Recycled plastic has the potential to enhance various construction materials, such as roofing tiles, paving blocks, and insulation. The aforementioned materials possess notable attributes such as high strength, low weight, and exceptional resistance to extreme temperatures and humidity. The objective of this study is to ascertain feasible alternatives for manufacturing road paver blocks utilizing plastic waste (Polyethene terephthalate (PET)), and M-sand (stone dust). Three variations of a discarded plastic cube measuring 150 mm × 150 mm × 150 mm were prepared for the experiment. The experimental findings indicated that a ratio of 1:4 was determined to be the most effective in achieving the desired level of compressive strength. I-section road and brick paver blocks were produced as an alternative to the traditional concrete ones. Compressive strength tests were performed on I-sections and brick paver blocks, revealing that the 1:4 mix ratio exhibited the highest average compressive strength for both materials. The findings indicated that including plastic waste positively impacted the compressive strength of the I-sections and brick paver blocks. Additionally, the quality grading of these materials was evaluated using an ultrasonic pulse velocity test. The ultrasonic pulse velocity test results demonstrated a high-quality grading for the I-sections and brick paver blocks. Scanning electron microscopy (SEM) tests assessed the microstructural behavior and performance. The results of this study demonstrate that incorporating plastic waste in combination with M-sand can effectively improve the mechanical characteristics of composite materials, rendering them viable for use in construction-related purposes. Full article

Most road surfaces globally are constructed using bituminous materials. The construction of new roads and the maintenance of existing ones demand a huge amount of virgin natural aggregates. Depletion of resources that takes place during the construction of the road has an impact on cost and also on the environment. Hence, there is a need to reduce virgin aggregate use for bituminous pavement construction. This can be achieved by utilizing sustainable materials such as marble waste and reclaimed asphalt pavement (RAP) in hot mix asphalt (HMA)-type road construction. This research work is focused on sustainable development goal (SDG) 12, exclusively on the target number 12.5 which describes the recycling and reuse of materials. However, no investigations were seen to be reported on the integrated utilization of sustainable materials and RAP in bituminous paver blocks. The bituminous mixes were evaluated based on strength and compared with the control mix in this study. Bituminous paver blocks were then cast using sustainable materials and tested in the laboratory to assess the performance of the blocks through a compression test, Cantabro loss test, and wheel rut test. The test results gave satisfactory values; hence, these bituminous blocks can be used for service maintenance of the pavement structures. The study indicates that using sustainable material along with RAP in blocks can provide an eco-friendly, easily maintainable pavement system which makes it a key approach to SDG 9 as well, in terms of innovative infrastructure solutions. Full article

Paver blocks are manufactured from zero-slump plain concrete, which is small element used for outdoor applications and flexible road surfaces. IS:15658 (2006) permits the use of 33- grade ordinary Portland cement (OPC) as the minimum for manufacturing paver blocks, but the usage of this type of cement is restricted in India nowadays. In this context, we have studied OPC 43-grade cement replaced by 30% Class F-grade fly ash and the addition of 0.0% and 0.5% polypropylene fibre (PPF) to evaluate the suitability of paver blocks in terms of the climatic conditions, movement of vehicles and road surfaces in India. The synergistic effect of the mechanical properties of paver blocks revealed that a 30% replacement of OPC with fly ash and 0.3% PPF is more suitable for the manufacturing of paver blocks. The obtained results from the reference mixes indicated that the mechanical properties of paver blocks have increased with respect to the age of the blocks. The present study is important for paver block manufacturers as it fulfils the mix design, strength and durability requirements for Indian roads associated with the utilization of waste materials such as fly ash. Additionally, the study will help the national economy increase by 20% in the future, along with the sustainability of virgin materials. Full article

This study investigates the feasibility of recycling various waste paving blocks as raw materials for concrete. The recycling rate of waste blocks in Korea remains around 11%. Therefore, three types of waste paving blocks, i.e., recycled clay-, granite-, and concrete block, were used as partial replacements for sand in a concrete mixture at 10%, 20%, and 30% replacement ratios. According to the Korean standards for concrete pavers and building bricks, compressive strength, flexural strength, and water absorption tests were conducted. In addition, UPV and unit weight tests were performed. The results showed that the performance of concrete mixtures decreased with the increasing replacement ratio of waste clay and concrete, while the addition of waste granite improved the properties of the mixtures. All the prepared concrete mixtures met the requirements specified in the standards, demonstrating that concrete incorporating waste blocks can be used as paving blocks and building bricks under limited conditions. Full article

In many developing countries, plastic waste management is left to citizens. This usually results in landfilling or hazardous open-air burning, leading to emissions that are harmful to human health and the environment. An easy, profitable, and clean method of processing and transforming the waste into value is required. In this context, this study provides an open-source methodology to transform low-density polyethylene drinking water sachets, into pavement blocks by using a streamlined do-it-yourself approach that requires only modest capital. Two different materials, sand, and ashes are evaluated as additives in plastic composites and the mechanical strength of the resulting blocks are tested for different proportion mix of plastic, sand, and ash. The best composite had an elastic modulus of 169 MPa, a compressive strength of 29 MPa, and a water absorptivity of 2.2%. The composite pavers can be sold at 100% profit while employing workers at 1.5× the minimum wage. In the West African region, this technology has the potential to produce 19 million pavement tiles from 28,000 tons of plastic water sachets annually in Ghana, Nigeria, and Liberia. This can contribute to waste management in the region while generating a gross revenue of 2.85 billion XOF (4.33 million USD). Full article

This article describes the recycling of coarse and fine fractions and powder from construction and demolition waste (CDW) using alkaline activation technology (geopolymerization). The CDW sample used corresponds to a mixture (mixed waste) of concrete (Co), ceramics (Ce) and masonry (M). Co, Ce and M (CDW-Mixed) powders were used as geopolymer precursors. As an alkaline activator, a mixture of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) was used. From CDW-Mixed, a hybrid cement added with 10% ordinary Portland cement (OPC) was synthesized to promote curing at room temperature (25 °C). From the alkali-activated hybrid cement and the incorporation of mixed recycled aggregates (gravel and sand), applications of mortars, concretes, fiber-reinforced materials and prefabricated units, such as solid blocks, perforated (hollow) blocks and pavers, were produced. The results of the physical–mechanical characterization validate the application potential of these CDW-based materials in the construction sector. Compressive strengths of up to 40.5 MPa for mortar and 36.9 MPa for concrete were obtained after 90 days of curing at room temperature ≈ 25 °C. Similarly, a life cycle analysis (LCA) associated with raw materials demonstrated the environmental sustainability (44% lower carbon footprint) of mixed alkali-activated CDWs compared to conventional materials based on OPC. Full article

Construction and Demolition Waste (CDW) is among the largest waste streams in the world. Therefore, within the Circular Economy concept, there is a growing interest in its reuse. The purpose of this work was to study the use of recycled aggregates (RAs) obtained by a specific separation method from CDW, replacing natural aggregates (NAs) in the manufacture of precast concrete elements, such as kerbstones and paver blocks. The physical and technological properties of precast products formulated with RAs were analysed in accordance with current regulations, comparing them with those of commercial products manufactured with NAs. The results indicated that partial or total substitution of NAs by RAs increased the water absorption and apparent porosity values of the precast elements while reducing the bulk density and compressive strength. However, all units manufactured with RAs showed breaking load values higher than the minimum required by EN 1338 and, in some cases, slightly higher average tensile strength values than the reference material. In addition, some of the compositions including RAs gave rise to pieces that, according to their flexural strength, were classified as class 1 and marked S in accordance with EN 1340. According to abrasion resistance, in most cases, the precast elements are classified as Class 4 and I (≤20 mm). Finally, precast concrete produced from RAs satisfies the tolerance requirements for classification as class 3 (≤1.5 kg m⁻²). Therefore, it could be suitable for use in high pedestrian or traffic areas. Full article

This paper presents an eco-friendly, low-impact development (LID) approach, developed and implemented at a car wash site for a cleaner and greener environment. In this approach, the contaminated water discharged after car washing is treated as it is directed through an engineered, ecology-based water-management design. The design involves poplar (Populus deltoides) trees, Silva Cells^®, and Fly-ash based Geopolymer concrete pavers working collectively to minimize the percolation of contaminants into the soil. In this novel system, each component has a vital role. For instance, the extensive roots of the poplar trees enable water filtration owing to phytoremediation effect; while the Silva Cells^® promote stormwater management, planting of poplar trees and serve as a foundation for paver blocks. Lastly, the paver blocks made from industrial waste allow it to withstand urban load and infiltrate water runoff, thereby reducing runoff quantities. To evaluate the efficacy of contaminant uptake by this system, pH, electrical conductivity and turbidity, which are indicators of water quality levels, were monitored pre- and post-treatment. The percentage change in total dissolved solids indicates the potential of this treatment system for effective treatment of the contaminated car wash water. Full article

The importance of permeable and pervious pavements in reducing urban stormwater runoff and improving water quality is growing. Here, a new pervious pavement block material based on recycled polyethylene terephthalate (PET) waste is introduced, which could contribute to reducing global plastic waste via PET’s utilization for construction material fabrication. The engineering properties and durability of recycled PET aggregate (RPA) pervious blocks are verified through flexural tests, in situ permeability tests, clogging tests, and freeze-thaw durability tests, and their cost-effectiveness is assessed by comparison with existing permeable/pervious pavers. Their engineering and economic characteristics confirm that the RPA pervious blocks are suitable for use in urban paving. Full article

Changes in weather patterns directly impact urban transport infrastructures. The increase in temperature and the ongoing precipitation changes should be handled and managed more frequently. In urban areas, most of the soil is impermeable and water hardly infiltrates into the subsoil. Permeable pavement is a technology that helps mitigate the effects of urban heat islands and surface impermeabilization. Porous concrete for pedestrian pavements ensures good structural, functional, and environmental performances. A pervious concrete mix differs from a conventional one in terms of the gradation of aggregates, namely, a lack of fine aggregates. The material porosity (on average 20%) causes compressive and flexural strengths lower than those of traditional concrete. The material is suitable for low-load pavements where the passage of motorized vehicles is forbidden or occasional. The pavement can be laid either monolithically or modularly, using two operating systems: returning water to underground aquifers and reducing runoff. The latter is the most frequently adopted in urban areas, where pedestrian and interdicted to motorized vehicle areas form a continuous and distributed network. In a common urban quarter, where 80% of the surface is impermeable, porous concrete pavements could cover up to 6% of the surface and provide architectural and aesthetic value for the environment. Full article