Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: closed (31 March 2021) | Viewed by 42968

Share This Special Issue

Special Issue Editors

Prof. Dr. César Medina Martínez

E-Mail Website
Guest Editor

Universidad de Extremadura, Instituto Universitario de Investigación para el Desarrollo Territorial Sostenible (INTERRA), Cáceres, Spain
Interests: recycling and waste materials in material-based cements; recycled concretes; alternative binders; durability; civil engineering; service life design; new interfacial transition zone in recycled concretes; life cycle assessment; real applications
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Holmer Savastano Junior

E-Mail Website
Guest Editor

Universidade de Sao Paulo - USP, Sao Paulo, Brazil
Interests: nonconventional materials; innovative construction; alternative binders; fiber cement composites; vegetable fiber; bamboo for construction; sustainability; durability; rural construction; residue recycling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, investigations focusing on nonconventional materials have been gaining attention in research, development and innovation. Aiming to bring together contributions from the more active international groups in this field, we are organizing this Special Issue on "Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing”. The main envisaged topics for the Special Issue are as follows: engineered vegetable and other natural fibers as reinforcing elements; alternative inorganic binders based on agricultural and industrial wastes; new secondary materials from waste in the manufacture of eco-concretes; processing and characterization of nonconventional cementitious composites; durable and robust housing solutions; low-embodied-energy constructive components and systems.

The main envisaged audience includes academic and industrial fellows interested in research, development and innovation in inorganic/organic bonded composites, efficient processing and eco-design of constructive solutions, contributing to the implementation of circular economy concepts in the construction sector. This Special Issue can be used in graduate and undergraduate courses in subjects such as civil engineering, environmental engineering, material science, biosystems engineering and architecture.

Many innovative solutions (such as bamboo-based components, additive manufacturing and the development of constructive systems for the optimization of construction/deconstruction operations) are increasingly being used both in developing and industrialized regions of the planet. There are key aspects to be understood for the correct preparation of residual or recycled materials before they are put into real-scale utilization. Binders and concretes are considered an important source of research for this kind of application as they can be designed for partial or even total substitution of conventional ones such as ordinary Portland cement or natural aggregates. The other important topics involve processing, characterization, durability studies and proper utilization of those new categories of materials. The papers will bring a complete overview of the main concepts and information needed for the development of innovative construction and the design of building components based on alternative materials and techniques.

Prof. César Medina Martínez
Prof. Holmer Savastano Junior
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Mineral additions for cement-based materials
New secondary materials from waste for eco-concretes
Phase-change materials and fiber-reinforced composites
Vegetable fibers for civil construction applications
Durability assessment of nonconventional materials
Engineered bamboo-, particleboard- and wood-related materials
Life cycle assessment applied to civil construction
Eco-design approach and 3D-printing-related technologies
New processes for construction and deconstruction
Earth-based construction materials

Published Papers (14 papers)

Download All Papers

Research

Jump to: Review

15 pages, 1617 KiB

Open AccessEditor’s ChoiceArticle

Quantitative Comparison of Binary Mix of Agro-Industrial Pozzolanic Additions for Elaborating Ternary Cements: Kinetic Parameters

by Ernesto Villar-Cociña, Moisés Frías, Holmer Savastano, Loic Rodier, María Isabel Sánchez de Rojas, Isabel Fuencisla Sáez del Bosque and César Medina

Materials 2021, 14(11), 2944; https://doi.org/10.3390/ma14112944 - 29 May 2021

Cited by 4 | Viewed by 1667

Abstract

In this research work, the quantitative characterization of a binary blend comprised of two pozzolans (sugar cane straw (SCSA)–sugar cane bagasse ashes (SCBA), bamboo leaf ash (BLAsh)–SCBA and paper sludge (PS)–fly ash (FA)) taking into account the calculated values of the kinetic parameters of the reaction in the pozzolan/calcium hydroxide system is shown. The paper shows the most significant and important results obtained by the authors in the quantitative assessment (calculation of kinetic parameters) of the pozzolanic reaction of different mixtures of pozzolanic materials that are residues from agriculture or industrial processes. This allows a direct and rigorous comparison of the pozzolanic activity of the binary combinations of materials. The values of the kinetic parameters (reaction rate constant or activation free energy) constitute a very precise quantitative index of the pozzolanic activity of the binary combinations of materials, which is very useful for its employment in the elaboration of ternary cements. This paper shows that the binary blends 1SCBA60Blash40, 1SCBA50Blash50, 1SCBA70Blash30 have a very high pozzolanic reactivity followed by PSLSFA, 2SCBA50SCSA50, PSISFA and SCWI. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

17 pages, 4821 KiB

Open AccessArticle

Characterization of Mechanical and Hygroscopic Properties of Individual Canes of Reed

by Montaña Jiménez-Espada, Daniel Herrero-Adán and Rafael González-Escobar

Materials 2021, 14(9), 2193; https://doi.org/10.3390/ma14092193 - 24 Apr 2021

Cited by 6 | Viewed by 2019

Abstract

The search for sustainability has led to the utilization of more ecological materials with at least, a similar structural performance to those used at present. In this regard, reed fits the environmental and structural requirements as it is a sustainable and biodegradable lignin-cellulose material with remarkable mechanical properties. This research confirms the reed’s structural efficiency as it demonstrates that it has excellent strength and stiffness in relation to its density. The reed anisotropy has a large impact on its properties. Indeed, the strength and stiffness parallel to the fibers are clearly higher than in the perpendicular direction. The results confirm that strength and stiffness decrease with the moisture content and nodes act as reinforcement in compression and bending. If compared with steel, timber and concrete, the reed possesses the highest value for strength. Hence, reed constitutes a strong candidate for environmentally friendly engineering. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

18 pages, 4324 KiB

Open AccessArticle

Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes

by Laura Caneda-Martínez, Manuel Monasterio, Jaime Moreno-Juez, Sagrario Martínez-Ramírez, Rosario García and Moisés Frías

Materials 2021, 14(5), 1299; https://doi.org/10.3390/ma14051299 - 08 Mar 2021

Cited by 44 | Viewed by 3204

Abstract

This work analyses the influence of fine concrete fractions (<5 mm) of different natures —calcareous (HcG) and siliceous (HsT)—obtained from construction and demolition waste (C&DW) on the behaviour of blended cement pastes with partial replacements between 5 and 10%. The two C&DW fractions were characterised by different instrumental techniques. Subsequently, their lime-fixing capacity and the physico-mechanical properties of the blended cement pastes were analysed. Lastly, the environmental benefits of reusing these fine wastes in the manufacture of future eco-efficient cement pastes were examined. The results show that HsT and HcG exhibit weak pozzolanic activity, owing to their low reactive silica and alumina content. Despite this, the new cement pastes meet the physical and mechanical requirements of the existing regulations for common cements. It should be highlighted that the blended cement pastes initially showed a coarser pore network, but then they underwent a refinement process between 2 and 28 days, along with a gain in compressive strength, possibly due to the double pozzolanic and filler effect of the wastes. The environmental viability of the blended cements was evaluated in a Life Cycle Assessment (LCA) concluding that the overall environmental impact could be reduced in the same proportion of the replacement rate. This is in line with the Circular Economy goals and the 2030 Agenda for Sustainable Development. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

20 pages, 4850 KiB

Open AccessArticle

Eco-House Prototype Constructed with Alkali-Activated Blocks: Material Production, Characterization, Design, Construction, and Environmental Impact

by Rafael A. Robayo-Salazar, William Valencia-Saavedra, Sandra Ramírez-Benavides, Ruby Mejía de Gutiérrez and Armando Orobio

Materials 2021, 14(5), 1275; https://doi.org/10.3390/ma14051275 - 08 Mar 2021

Cited by 10 | Viewed by 3537

Abstract

The interest of the construction industry in alkali-activated materials has increased to the extent that these materials are recognized as alternatives to ordinary Portland cement-based materials in the quest for sustainable construction. This article presents the design and construction of a prototype of an eco-friendly house built from concrete blocks produced using alkali activation technology or geopolymerization. The prototype meets the requirements of the current Colombian Regulations for Earthquake Resistant Buildings (NSR-10) and includes standards related to the performance of the materials, design, and construction method for earthquake-resistant confined masonry of one- or two-story buildings. The alkali-activated blocks were obtained from different precursors (aluminosilicates), including a natural volcanic pozzolan, ground granulated blast furnace slag, fly ash, construction and demolition waste (concrete, ceramic, brick, and mortar), and red clay brick waste. The physical-mechanical characterization of the alkali-activated blocks allowed their classification according to the structural specifications of the Colombian Technical Standard NTC 4026 (equivalent to ASTM C90). The global warming potential (GWP) or “carbon footprint” attributed to the raw materials of alkali-activated blocks was lower (25.4–54.7%) than that of the reference blocks (ordinary Portland cement concrete blocks). These results demonstrate the potential of alkali-activated materials for application in the construction of eco-friendly houses. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

11 pages, 3468 KiB

Open AccessArticle

Use of a Handheld X-ray Fluorescence Analyser to Quantify Chloride Ions In Situ: A Case Study of Structural Repair

by Servando Chinchón-Payá, Julio E. Torres Martín, Nuria Rebolledo Ramos and Javier Sánchez Montero

Materials 2021, 14(3), 571; https://doi.org/10.3390/ma14030571 - 26 Jan 2021

Cited by 5 | Viewed by 1479

Abstract

To ensure that a structure will last throughout its service life, repairing reinforced concrete entails, among others, correctly marking off the area affected by aggressive agents that may deteriorate both the concrete and the steel. Chloride, the most damaging source of reinforcement corrosion, may diffuse to a greater or lesser distance from the surface depending on the ease of penetration. In this study, we calibrated a handheld X-ray fluorescence analyser (hXRF) and used it to quantify the chloride concentration in cement-based materials. The findings were verified against a series of samples of known concentration to establish a suitable correction factor. Chloride ions were quantified precisely and accurately with the hXRF instrument, and we calculated a correction factor of 1.16. The instrument and the information recorded were used to quantify the chloride ion content in different parts of an existing structure. The analyser identified apparently healthy areas that could, nonetheless, pose oxidation problems in the near future due to significant chloride concentration. Chloride quantification data at different depths can be used to draw diffusion or penetration profiles and to determine whether ion concentration around the reinforcement is within the recommended limits. The method developed can be applied in situ to quickly locate the most critical areas. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

15 pages, 5625 KiB

Open AccessArticle

Improving the Mechanical Properties of Sulfoaluminate Cement-Based Grouting Material by Incorporating Limestone Powder for a Double Fluid System

by Yanfeng Wang, Songhui Liu, Dongxing Xuan, Xuemao Guan and Haibo Zhang

Materials 2020, 13(21), 4854; https://doi.org/10.3390/ma13214854 - 29 Oct 2020

Cited by 8 | Viewed by 1739

Abstract

To improve the hardening performance of sulfoaluminate cement-based grouting material (SCGM) and reduce its cost, limestone powder was adopted to replace anhydrite in the control SCGM. The influence of the replacement rate of limestone powder on the hydration, hardening strength, expansion, and microstructure evolution of the SCGM was systematically researched. The results indicated that replacing anhydrite with limestone powder in SCGM can improve the flowability, shorten the setting time, and enhance the compressive strength at early and late stages. When the replacement rate of limestone powder was 20%, the compressive strength of SCGM for 6 h and 28 days increased by 146.41% and 22.33%, respectively. These enhancements were attributed to the fact that fine limestone powder can accelerate the early hydration reaction rate and promote the formation of ettringite due to its nucleation effect. Moreover, due to the presence of limestone powder, mono-carbonate (Mc) can be formed, which would densify the microstructure and refine the pore structure of the hardened SCGM. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

17 pages, 2960 KiB

Open AccessArticle

Effect of the Drying Method of Pine and Beech Wood on Fracture Toughness and Shear Yield Stress

by Daniel Chuchala, Jakub Sandak, Kazimierz A. Orlowski, Tomasz Muzinski, Marcin Lackowski and Tomasz Ochrymiuk

Materials 2020, 13(20), 4692; https://doi.org/10.3390/ma13204692 - 21 Oct 2020

Cited by 12 | Viewed by 2667

Abstract

The modern wood converting processes consists of several stages and material drying belongs to the most influencing future performances of products. The procedure of drying wood is usually realized between subsequent sawing operations, affecting significantly cutting conditions and general properties of material. An alternative methodology for determination of mechanical properties (fracture toughness and shear yield stress) based on cutting process analysis is presented here. Two wood species (pine and beech) representing soft and hard woods were investigated with respect to four diverse drying methods used in industry. Fracture toughness and shear yield stress were determined directly from the cutting power signal that was recorded while frame sawing. An original procedure for compensation of the wood density variation is proposed to generalize mechanical properties of wood and allow direct comparison between species and drying methods. Noticeable differences of fracture toughness and shear yield stress values were found among all drying techniques and for both species, but only for beech wood the differences were statistically significant. These observations provide a new highlight on the understanding of the effect of thermo-hydro modification of wood on mechanical performance of structures. It can be also highly useful to optimize woodworking machines by properly adjusting cutting power requirements. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

19 pages, 5554 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Concrete for Precast Blocks: Binary and Ternary Combination of Sewage Sludge Ash with Diverse Mineral Residue

by Francisco Baeza-Brotons, Jordi Payá, Oscar Galao, Marcos G. Alberti and Pedro Garcés

Materials 2020, 13(20), 4634; https://doi.org/10.3390/ma13204634 - 17 Oct 2020

Cited by 4 | Viewed by 2238

Abstract

This paper proposes binary and ternary combinations of sewage sludge ash (SSA) with fly ash (FA), marble dust (MD) and rice husk ash (RHA) as partial replacements of Portland cement in concretes with a similar dosage to that used in precast blocks, with very dry consistency. Several physical-mechanical tests were carried out on concrete specimens with curing ages of 28 and 90 days: density, water absorption, capillary water absorption, ultrasonic pulse velocity and compressive strength. The combinations of residues significantly improve the properties of the cementitious systems: 30% replacement of Portland cement provides strength values similar to the reference sample, showing the synergetic effects of the combination of the mineral additions. The significance of this research relies on the combined use of the mineral additions as well as the use of them for the precast block industry. The results show synergies among the additions and even that some of them showed relevant improvements when they are used in combination, performing better than when used individually. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

18 pages, 3508 KiB

Open AccessArticle

Control of Cracking in Textile Reinforced Concrete with Unresin Carbon Fibers

by Rui Neves and Diogo Felicíssimo

Materials 2020, 13(14), 3209; https://doi.org/10.3390/ma13143209 - 18 Jul 2020

Cited by 2 | Viewed by 2152

Abstract

Textile reinforced concrete (TRC) is an emerging construction material with interesting potential concerning sustainability, providing corrosion-free and lightweight solutions. Ordinarily, fiber bundles, impregnated with resin, are used. In this research the performance of reinforcement with unresin fibers is investigated. Control of cracking is considered the key performance factor and is assessed through tensile testing. However, economic and environmental aspects are addressed as well. Then, four different mixes/matrices were considered, without the addition of special/expensive admixtures. TRC ties were subject to direct tension tests, with load and deformation monitoring to assess the influence of mechanical reinforcement ratio on the cracking, failure and toughness of these composites, as well as of the matrix properties on the maximum load. It was observed that at a macro-level TRC behaves like conventional reinforced concrete, concerning crack control. Based on the maximum loads attained at the different composites, it was found that this particular TRC is economically viable. It is suggested that matrix workability may influence the maximum load. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

Review

Jump to: Research

29 pages, 2052 KiB

Open AccessReview

Recycled Fibers for Sustainable Hybrid Fiber Cement Based Material: A Review

by Ana Balea, Elena Fuente, M. Concepcion Monte, Angeles Blanco and Carlos Negro

Materials 2021, 14(9), 2408; https://doi.org/10.3390/ma14092408 - 05 May 2021

Cited by 16 | Viewed by 4462

Abstract

Reinforcing fibers have been widely used to improve physical and mechanical properties of cement-based materials. Most fiber reinforced composites (FRC) involve the use of a single type of fiber to improve cement properties, such as strength or ductility. To additionally improve other parameters, hybridization is required. Another key challenge, in the construction industry, is the implementation of green and sustainable strategies based on reducing raw materials consumption, designing novel structures with enhanced properties and low weight, and developing low environmental impact processes. Different recycled fibers have been used as raw materials to promote circular economy processes and new business opportunities in the cement-based sector. The valuable use of recycled fibers in hybrid FRC has already been proven and they improve both product quality and sustainability, but the generated knowledge is fragmented. This is the first review analyzing the use of recycled fibers in hybrid FRC and the hybridization effect on mechanical properties and workability of FRC. The paper compiles the best results and the optimal combinations of recycled fibers for hybrid FRC to identify key insights and gaps that may define future research to open new application fields for recycled hybrid FRC. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

19 pages, 371 KiB

Open AccessReview

Thermal Energy Storage by the Encapsulation of Phase Change Materials in Building Elements—A Review

by José Luis Reyez-Araiza, Jorge Pineda-Piñón, José M. López-Romero, José Ramón Gasca-Tirado, Moises Arroyo Contreras, Juan Carlos Jáuregui Correa, Luis Miguel Apátiga-Castro, Eric Mauricio Rivera-Muñoz, Rodrigo Rafael Velazquez-Castillo, José de Jesús Pérez Bueno and Alejandro Manzano-Ramirez

Materials 2021, 14(6), 1420; https://doi.org/10.3390/ma14061420 - 15 Mar 2021

Cited by 34 | Viewed by 3183

Abstract

The energy sector is one of the fields of interest for different nations around the world. Due to the current fossil fuel crisis, the scientific community develops new energy-saving experiences to address this concern. Buildings are one of the elements of higher energy consumption, so the generation of knowledge and technological development may offer solutions to this energy demand, which are more than welcome. Phase change materials (PCMs) included in building elements such as wall panels, blocks, panels or coatings, for heating and cooling applications have been shown, when heating, to increase the heat storage capacity by absorbing heat as latent heat. Therefore, the use of latent heat storage systems using phase change materials (PCMs) has been investigated within the last two decades. In the present review, the macro and micro encapsulation methods for construction materials are reviewed, the former being the most viable method of inclusion of PCMs in construction elements. In addition, based on the analysis of the existing papers on the encapsulation process of PCMs, the importance to pay more attention to the bio-based PCMs is shown, since more research is needed to process such PCMs. To determine its thermophysical and mechanical behavior at the micro and macro levels, in order to see the feasibility of substituting petroleum-based PCMs with a more environmentally friendly bio-based one, a section devoted to the excellent PCM with lightweight aggregate (PCM-LWA concrete) is presented due to the lack of description given in other reviews. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

31 pages, 795 KiB

Open AccessEditor’s ChoiceReview

Magnesia (MgO) Production and Characterization, and Its Influence on the Performance of Cementitious Materials: A Review

by José Nobre, Hawreen Ahmed, Miguel Bravo, Luís Evangelista and Jorge de Brito

Materials 2020, 13(21), 4752; https://doi.org/10.3390/ma13214752 - 23 Oct 2020

Cited by 55 | Viewed by 5404

Abstract

This paper presents a literature review concerning the characteristics of MgO (magnesium oxide or magnesia) and its application in cementitious materials. It starts with the characterization of MgO in terms of production processes, calcination temperatures, reactivity, and physical properties. Relationships between different MgO characteristics are established. Then, the influence of MgO incorporation on the properties of cementitious materials is investigated. The mechanical strength and durability behaviour of cement pastes, mortars and concrete mixes made with MgO are discussed. The studied properties of MgO–cement mixes include compressive strength, flexural strength, tensile strength, modulus of elasticity, water absorption, porosity, carbonation, chloride ion penetration, shrinkage, expansion, and hydration degree. In addition, microscopic analyses of MgO-cement mixes are also assessed. Summarizing the results of different studies, it is concluded that MgO incorporation in cementitious materials generally decreases the mechanical strength and shrinkage, and increases the porosity, expansion, carbonation and chloride ion migration. However, it should be emphasized that the properties of the specific MgO used (mainly the calcination temperature, the reactivity and the surface area) have a significant influence on the characteristics of the cementitious materials produced. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

25 pages, 14366 KiB

Open AccessReview

Densification of Bamboo: State of the Art

by Marzieh Kadivar, Christian Gauss, Khosrow Ghavami and Holmer Savastano, Jr.

Materials 2020, 13(19), 4346; https://doi.org/10.3390/ma13194346 - 29 Sep 2020

Cited by 31 | Viewed by 4800

Abstract

Densification processes are used to improve the mechanical and physical properties of lignocellulose materials by either collapsing the cell cavities or by filling up the pores, consequently reducing the void volume fraction. This paper focuses on an extensive review of bamboo densification process, which is achieved by compressing the material in the direction perpendicular to the fibers using mainly two different techniques: an open system, thermo-mechanical (TM), or a closed system, viscoelastic-thermal-compression (VTC). The main aim of bamboo densification is to decrease its heterogeneity, as well as to improve its mechanical and physical performance. In addition, densification may occur during the manufacturing of bamboo products in which hot-pressing processes are used to mold bamboo panels. There are over 1600 publications about bamboo, concentrated in the recent decade, mainly about engineered materials. Although several papers regarding bamboo and wood densification are available, very few studies have comprehensively investigated the densification process solely through compression of natural bamboo culms. According to the literature, applying a combination of compression of 6–12 MPa at temperatures between 120–170 °C for 8–20 min can produce materials with higher strength in comparison to the mechanical properties of natural bamboo. The majority of research on bamboo densification indicates that the modified material results in improved properties in terms of density, hardness, bending strength, stiffness, and durability. This paper provides a review that consolidates knowledge on the concept of bamboo culm densification, discusses the roles of parameters that control the process, ascertains the best practice, and finally determines gaps in this field of knowledge. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures

Figure 1

13 pages, 2944 KiB

Open AccessReview

Wool-Reinforced Cement Based Composites

by Daria Jóźwiak-Niedźwiedzka and Alessandro P. Fantilli

Materials 2020, 13(16), 3590; https://doi.org/10.3390/ma13163590 - 14 Aug 2020

Cited by 25 | Viewed by 2926

Abstract

In this paper, an overview of the latest research activities in the field of cement-based composites incorporating sheep wool reinforcement is presented. First, the characteristics of this type of natural fibre are described. Then, the current use of sheep wool fibres in cement-based composites is discussed. The research problems regarding the properties of cement matrix composites reinforced with sheep wool are divided into four groups: thermal and acoustic properties, mechanical behavior, durability issues, and microstructure aspects. The latter two groups are analysed separately, because both durability and microstructure are of particular importance for future applications of wool reinforcement. Finally, the main directions of future researches are presented. Full article

(This article belongs to the Special Issue Novel and Sustainable Civil Engineering Materials: Eco-Design, Properties and New Processing)

► Show Figures