In recent years, there has been an increased focus on the research of earthen construction, driven by the rising demand for low-cost and sustainable building materials. Numerous studies have investigated the properties of compressed earth blocks (CEBs), however, very few have examined the properties of earth-based mortar. Mortar is an essential component and further investigation is required to enhance the mechanical performance of CEB structures. The study focuses on raw earth mortar (REM), which is a rudimentary mix of water with natural earth consisting of sand, silt and clay. Through experimental investigation, the fresh and hardened properties of three REM mixes were examined to determine the influence of cement stabilisation and jute fibre reinforcement. Shear triplet CEB assemblages were manufactured and tested to determine the initial shear strength of each mortar mix. The addition of 20 mm jute fibre at 0.25 % by weight increased the compressive and flexural strength of cement-stabilised raw earth mortar by 12 % and 20 % respectively. The addition of jute fibre also enhanced the initial shear strength, angle of internal friction and coefficient of friction during shear triplet testing. Finite element analysis (FEA) was undertaken to model the failure mechanism of the CEB assemblages, employing the use of cohesive zone modelling. The results of the FEA provided a satisfactory correspondence to the behaviour observed during experimental analysis and were within +/- 5.0 % of the expected values. The outcome of this investigation demonstrates the potential of REM and contributes to the development of low-cost and sustainable earth construction.

High-strength mortar (HSM) gradually has wide applications due to its exceptional strength, micro-expansion properties, and excellent fluidity. Behavior deterioration of structures in saline soil areas is primarily attributed to freeze-thaw cycles and sulfate attack. In this study, the coupling effect of freeze-thaw cycles and sulfate attack on the appearance, mass loss, and relative dynamic elastic modulus of HSM was investigated during erosion. Then, compressive experiments were conducted to assess the mechanical properties of HSM subjected to both freeze-thaw cycles and sulfate attack. The influences of coupling freeze-thaw cycles and sulfate attack on the compressive properties of HSM were quantified through regression analysis of experimental results. Empirical models for compressive stress-strain curves and damage constitutive behavior of HSM were developed, taking the coupled adverse effect into account. The results indicate that the coupled effect of freeze-thaw cycles and sulfate attack causes performance deterioration of HSM. The empirical models reproduce the compressive behaviors of HSM subjected to freeze-thaw cycles and sulfate attack.

The socio-economic growth of a nation depends heavily on the availability of adequate infrastructure, which relies on essential materials like river sand (RS) and cement. However, the rising demand for RS, combined with its excessive extraction causing ecological damage, and its increasing cost, has raised significant concerns. At the same time, the production of cement contributes significantly to environmental damage, especially through CO2 emissions. In this scenario geopolymer technology has emerged as a sustainable alternative to cement, offering environmental benefits and reducing the carbon footprint of construction materials. This study investigates the impact of replacing RS with copper slag (CS) and laterite soil (LS) in geopolymer mortar (GM) on key properties such as setting time, flowability, compressive strength, and microstructure. The results showed that as LS content increased, setting time and flowability decreased considerably, while increasing CS content caused a reduction in these values. Unlike the other observed parameters, the compressive strength values showed no distinct upward or downward trend. Moreover, the microstructural analysis, including SEM, EDS, XRD, FTIR, TGA and BET, provided valuable insights to support the observed results across various mix designs. Overall, the findings highlight that optimised binary blends of CS, LS and RS not only improved the compressive strength but also enhanced the microstructural characteristics of geopolymer mortar, reinforcing their potential as sustainable and high-performance alternatives to conventional fine aggregates.

Freeze-thaw cycles coupled with sulfate attack represent one of the most challenging service environments for concrete. This study aims to enhance the durability of concrete materials in environments characterized by sulfate attack and severe freeze-thaw conditions. Specifically, it investigates the deterioration laws and evolution models of mortar materials containing silica fume under both freeze-thaw and coupled freeze-thaw/sulfate attack conditions. Mortar specimens with varying silica fume contents (0%, 6%, 8%, and 10%) were prepared and subjected to single freeze-thaw and coupled freeze-thaw-sulfate attack tests to examine the impact of different silica fume dosages on the durability of mortar materials under these harsh conditions. Additionally, a quantitative assessment model for damage evolution was established using the entropy weight method and Wiener process model. The research findings indicate that silica fume significantly enhances the sulfate resistance and freeze-thaw durability of mortar materials, with an optimal dosage of 10%. Within the scope of this study, higher silica fume content results in a greater number of sulfate attack-freeze-thaw cycles the mortar can endure before damage and failure, thereby extending its service life. Based on the Wiener stochastic process damage model and field data, it is predicted that the service life of mortar containing 10% silica fume increases most notably to 36.6 years, representing a relative improvement of 45.8 % compared to mortar without silica fume. These results provide valuable references and guidance for the design and construction of concrete structures in regions characterized by high-cold temperatures and salt- corrosive soils.

Sustainability is defined as the process of developing and responsibly sustaining a healthy built environment based on resource-efficient and ecological principles. When it comes to sustainability, earthen construction is a good choice because of its minimal carbon impact and lower operating expenses. This study investigates the cost comparison between Alker and a reinforced concrete office with a dimension of 6 x 6 m. Alker is a stabilised form of earthen building. Based on the dry weight of the soil, it contains 10% gypsum, 2% lime, and 20%-22% water. Shredded plastic waste (SPW) was added to Alker to improve its properties with the addition of the environmental effect of plastic waste. The results showed that the office built with reinforced concrete had a total cost of Turkish Lira;119 348.57 (6630), whereas the building built with Alker materials had a total cost of Turkish Lira;103 474.19 (5748). Therefore, offices built with Alker's added SPW are 13% cheaper than offices built with reinforced concrete. Alker modified with shredded plastic waste has been demonstrated to be a sustainable building material with enhanced properties.

The production of agricultural residues causes environmental pollution, especially in regions with intensive horticultural production. The solution is to maximise the use of residues, applying the 'zero waste' model and using them to develop construction materials. Natural fibres used to reinforce materials have environmental and economic benefits due to their low cost. This research presents an innovative characterisation using an inverted-plate optical microscope, a high-resolution scanning electron microscope (HRSEM) and a 3D X-ray microscope. A physico-mechanical and chemical characterisation of horticultural fibres was also conducted. The fibres analysed were those produced in the highest quantities, including those from tomatoes, peppers, zucchinis, cucumbers and aubergines. The viability of these natural fibres for use as reinforcements in biocomposites was investigated. The analysis centred on studying the microstructure, porosity, chemical composition, tensile strength, water absorption and environmental degradation of the natural fibres. The results showed a porosity ranging from 47.44% to 61.18%, which contributes to the lightness of the materials. Cucumber stems have a higher tensile strength than the other stems, with an average value of 19.83 MPa. The SEM analysis showed a similar chemical composition of the scanned fibres. Finally, the life cycle of the materials made from horticultural residue was analysed, and negative GWP (global warming potential) CO2eq values were obtained for two of the proposed materials, such as stabilised soil reinforced with agricultural fibres and insulation panels made of agricultural fibres.

The construction industry is increasingly focusing on sustainability, creating a need for innovative materials. This comprehensive review examines the potential of calcined clays and nanoclays in enhancing construction materials and promoting resilient infrastructure. It emphasises their role in improving performance and supporting environmental conservation in sustainable development. The review discusses how varying proportions of calcined clays and nanoclays impact the performance of pavement materials, especially when combined with bitumen in asphalt mixtures. It highlights their benefits, including reduced chloride penetration, enhanced water resistance, and improved soil conductivity. Overall, the review suggests that the strategic integration of calcined clays and nanoclays into construction materials can enhance durability, optimise resource use, and support environmental sustainability.

This study investigates the potential of Termite Hill Soil (THS) as a sustainable partial replacement for Ordinary Portland Cement (OPC) in mortar production. The experimental program involved preparing mortar mixtures with 0%, 5%, 10%, 15%, and 20% THS replacement levels by weight while maintaining a constant water-to-cement ratio. Various physical, chemical, fresh, mechanical, durability and microstructural properties were studied. The findings indicate that THS possesses pozzolanic properties. Workability and setting time decreased, while the water demand for normal consistency increased as THS content rose. The compressive strength results showed a 9.5% improvement at 5% THS and achieved 98% of the control mix at 10% THS. Additionally, THS5 and THS10 significantly enhanced bulk density, ultrasonic pulse velocity, and compressive strength, particularly in the latter ages of mortar. The microstructural analysis confirmed improved density in these mixtures, along with respectable thermal properties and FTIR spectra. Overall, THS showcases promising and commendable performance, and its utilization as a substitute for OPC not only reduces the carbon footprint of cement production but also promotes sustainability within the construction industry.

Geopolymer-based cementitious materials known for their robust durability and lower environmental impact make them an ideal choice for sustainable construction. The main focus of this study is to understand the influence of chemical admixtures which plays a pivotal role in improving the properties of geopolymer mortar (GM). This research integrates various chemical admixtures, including calcium chloride, sodium sulphate, sodium hexametaphosphate, and MasterGlenium SKY 8233 (SKY) which falls under the category of either accelerators, retarders, or superplasticisers. Assessments were conducted on the fresh and hardened states of flyashbased GM mixes with varying proportion of river sand (RS), laterite soil (LS) and copper slag (CS), encompassing flowability, setting times, compressive strength, durability study in aggressive environmental conditions and microstructural analyses after 56 days of ambient curing. Findings reveal that calcium chloride and sodium sulphate efficiently decrease the initial and final setting times of the geopolymer paste, highlighting their roles as accelerators, with calcium chloride showing greater efficacy than sodium sulphate. On the other hand, sodium hexametaphosphate serves as a retarder, substantially extending the initial setting time of the geopolymer paste. Introducing the modified polycarboxylic ether (PCE) based superplasticiser SKY into the mortar matrix caused the initial setting time to be extended and resulted in a slight drop in compressive strength compared to the other mixes. Durability tests confirmed the superior resistance of GM mixes to harsh environments like acid, sulphate, and marine water exposure. These findings highlight the potential for tailoring geopolymer blends to achieve desired properties under ambient curing conditions using chemical admixtures.

This work investigates the effects of substituting natural sand with excavated soil sand in the formulation of hydraulic mortar developed from a self-compacting concrete (SCC). Four excavated soil sand deposits were studied to assess their physicochemical properties. Subsequently, a reference mortar (RM) was designed using the concrete equivalent mortar method. Furthermore, the effect of incorporating 30% of excavation soil sand under different moisture conditions (natural storage conditions, dry and saturated surface dry state) on the properties of mortar is studied. Spreading tests were carried out to observe how the rheological properties evolve over time. The study includes compressive and flexural strength tests at 2, 7, 14 and 28 days. The results showed that some sands had densities similar to those of natural alluvial sand, while others had lower densities. Water absorption values varied considerably from one sand to another, with some showing values ranging from 1% to 6%, while other sands had values of up to 10%. The results of spreading tests indicate that mortar made with sand in a saturated dry-surface state is more fluid than mortar made with sand in a dry state. Under all conditions, all mortars lose their fluidity over time. The variation in compressive strength among all excavated soil sand mortars compared to the reference mortar remained below 10% at 2 and 28 days, except for one sand with a high clay content. The incorporation of excavated soil sand at this percentage as a substitute for river sand led to an enhancement in the flexural strength of the mortar, with improvements of 40% and 50% observed for certain types of excavated sand. The statistical study revealed a strong relationship between the properties of the sand (in particular, the fines content and their nature, as well as the sand skeleton) and its saturation state, the flowability and the compressive strength of the mortar.