Sustainable Mortars Research Articles

Integrated Techno-Environmental Analysis of Finely Ground Silica Sand in Sustainable Mortar Production

The environmental impacts of cement production are becoming more urgent concerns. This study examined the mechanical characteristics of cement when it is partially replaced with finely crushed sand. The experimental program consisted of three different levels of sand fineness of 459 m2/kg, 497 m2/kg, and 543 m2/kg, as well as four substitution ratios of 10%, 20%, 30%, and 40%. A total of thirteen combinations were formulated and then evaluated. The results demonstrated that increasing sand fineness from 459 m2/kg to 543 m2/kg substantially impacted the compressive strength (CS), increasing it by up to 30%, and increasing the substitution ratio from 10% to 40% reduced the mechanical strength by roughly 40%. An extensive techno-environmental evaluation showed that replacing cement with finely crushed sand is technically feasible and environmentally advantageous. This technique can decrease carbon dioxide (CO2) emissions by around 40%, emphasizing its ecological benefits and coinciding with worldwide initiatives to decrease the environmental impact of construction materials. In summary, this study demonstrates the advantages of improving the mechanical characteristics of cement while minimizing its ecological footprint. It suggests that finely crushed sand can be used as a sustainable alternative in cement manufacturing, promoting the use of more environmentally friendly construction methods.

Impact of Elevated Temperature Exposure on Some Properties of Sustainable Mortar with Plastic Bag Waste

Impact of Elevated Temperature Exposure on Some Properties of Sustainable Mortar with Plastic Bag Waste

Experimental investigations on sustainable mortar containing mining tailing as partial replacement of fine aggregate

ABSTRACT The reuse of mining tailings contributes to minimizing the impact associated with the extraction of mineral resources. In this study, tailings were classified according to their mineralogy, and then 10% to 50% of the fine aggregate in the concrete was replaced by tailings. It was found a substantial enhancement in the compressive strength of concrete when incorporating mine tailings, increasing by 12% to 18%. The favourable outcomes can be attributed to the mineralogical compositions of the tailings. This innovative approach contributes to a noteworthy reduction in the environmental footprint associated with mining activities.

Experimental investigation of the use of crushed clay brick on the properties of sustainable mortar

In the world, millions of tons of construction waste are generated annually, due to the boom of this sector, and brick waste is the most prominent. The purpose of the research was to study the properties of the mortar with the partial substitution of fine aggregate by brick residues (BR), using an experimental methodology based on mortar samples in doses of 10%, 20%, 30% and 40% with brick residues, which were subjected to mortar tests and masonry tests. The results showed that the mortar sample with the best performance was 10% BR, achieving in the mortar tests an increase with respect to conventional mortar of 1.58% in compressive strength, 3.99% in flexural strength, 15.61% in tensile strength, while in the masonry tests the increase was 12.19% in compressive strength in prisms, 33.20% in bond strength and 3.82% in diagonal compressive strength. It was concluded that the substitution of fine aggregate by BR is feasible up to 10%, achieving an optimum improvement in the mechanical properties of the mortar.

Leveraging Machine Learning for Designing Sustainable Mortars with Non-Encapsulated PCMs

Leveraging Machine Learning for Designing Sustainable Mortars with Non-Encapsulated PCMs

Integrated Use of Furnace Bottom Ash as Fine Aggregate and Cement Replacement for Sustainable Mortar Production.

Recycling fly ash (FA) and furnace bottom ash (FBA) help with reducing greenhouse gas emissions, conserving natural resources, and minimizing waste accumulation. However, research on recycling FBA is progressing more slowly compared to FA. This research aims to investigate the combined use of FBA as a replacement for both fine aggregate and cement and its influence on the performance of mortar. The findings indicated that incorporating 25% FBA as a fine aggregate replacement and 10% or 20% ground FBA (GFBA) as a cement replacement significantly enhanced compressive strength after 28 and 56 days. Flexural strength was comparable to control mortar at 28 days and superior at 56 days. However, increasing the FBA content beyond 25% as a fine aggregate replacement reduced workability and increased porosity, which negatively affected mechanical performance and water absorption. Microstructural analyses revealed denser and more compact structures in the mortar with combined FBA replacement for both fine aggregate and cement, specifically 25% as a fine aggregate replacement and 10% and 20% as cement replacements. Optimal performance was noted in mixtures with Ca/Si and Ca/Al ratios within the ranges of 1.8-1.5 and 0.24-0.19, respectively. Trace element leaching analysis has not shown significant differences between GFBA, FA, and OPC. Regarding environmental impact assessment, using FBA as a fine aggregate replacement did not show a significant reduction in CO2 emissions, but replacing cement with FBA reduced emissions remarkably. Generally, using FBA as a replacement for both fine aggregate and cement in mortar enhances compressive and flexural strengths at optimal levels, promotes sustainability by reducing landfill waste and CO2 emissions, and supports cleaner production practices despite some workability challenges.

Effect of rice husk ash and coconut coir fiber on cement mortar: Enhancing sustainability and efficiency in buildings

This research investigated energy efficiency, insulation properties together with strength properties and cost-effectiveness, focusing on developing a sustainable mortar. Cement: sand of 1: 2.25 (by weight) mortar with varying rice husk ash (RHA) and coconut coir (CC) fiber contents were prepared. Physical, microstructure, strength, durability, and thermal performances were experimentally examined. Life cycle assessment and cost analysis were numerically examined. Adding CC fiber reduced the longer final setting time found with the RHA-based mortar. With 20 % RHA and 0.5 % CC fiber, weight was reduced by 9.2 % (compared to the conventional mortar), promising a lightweight mortar. Flexural strength was increased by 8.6 % with 0.5 % CC fiber addition, this was further increased to 13.6 % with 10 % RHA in the mixture. 20 % RHA and 0.5 % CC fiber mortar exhibits a temperature difference of 8.7°C, whereas the conventional mortar exhibits a temperature difference of 2.5°C, indicating a reduced thermal conductivity of the RHA-CC fiber mortar. This mortar reduced the CO2 emission, energy consumption, and manufacturing cost by 17.7 %, 13.6 % and 7.0 %, respectively, indicating the sustainability. A cost-effective and energy-efficient lightweight mortar with enhanced thermal insulation and flexural strength was achieved by reinforcing the conventional mortar with 20 % RHA and 0.5 % CC fiber for the applications of dwellings.

Durability analysis of sustainable mortars with biomass fly ash as high-volume replacement of Portland cement

Utilization of various supplementary cementitious materials was in the last decades considered beneficial for the replacement of the energy-intensive Portland cement to meet sustainable targets. However, structural changes in energy production and heavy industry in Europe significantly limit the availability of coal fly ash and blast furnace slag for blended cement production. On the other hand, the increasing production of biomass ash (BA) presents not only challenges for its disposal but also new opportunities for the concrete industry. In this paper, the durability of cement composites containing up to 70 wt% of BA as Portland cement (PC) replacement was analyzed, taking into consideration also microstructure and mechanical properties. The experimental results showed a preservation of good mechanical performance up to the 30 wt% limit. The freeze-thaw resistance was not affected significantly up to the 40 wt% BA dosage during the first 300 cycles. The analyzed composites also exhibited a good overall resistance to alkali silica reaction- and sulfate-induced expansion up to the 50 wt% PC replacement. BA can thus be considered as a prospective future alternative to coal fly ash and blast furnace slag to meet the sustainable development goals in the building industry.

Shrinkage characteristics of sustainable mortar and concrete with alkali-activated slag and fly ash Binders: A focused review

Alkali-activated binders are emerging as promising sustainable alternatives to ordinary Portland cement (OPC) due to their lower environmental footprint. They offer competitive mechanical properties and enhanced durability, making them attractive options for a wide range of construction and infrastructure applications. This paper is a focused review of key findings related to the shrinkage characteristics of mortar and concrete with alkali-activated slag and fly ash binders. Shrinkage induces nonuniform deformations in mortar/concrete, leading to the development of internal tensile stresses and the formation of cracks. Such cracks may be sufficiently large to facilitate the penetration of harmful substances, which may compromise the integrity of structural elements. Several studies indicated that the combination of fly ash and slag precursors in appropriate proportions produces mortar with favorable shrinkage cracks when compared to mortar with individual binders. This article discusses the influence of the following factors on shrinkage characteristics: binder type, binder proportions, water/binder ratio, binder content, aggregate content, alkaline activator type, and concentration. The article compares the shrinkage of mortar/concrete prepared using mostly alkali-activated slag and fly ash binders and compares their shrinkage response to OPC. Shrinkage types evaluated include chemical shrinkage, autogenous shrinkage, and drying shrinkage. Shrinkage responses reported in this article include the sample curing method and environment as they are known to influence durability, strength, and shrinkage characteristics. In general, mortar/concrete with alkali-activated fly ash and slag experience higher shrinkage rates than conventional concrete with OPC binders. The study further explores shrinkage mechanisms and methods to mitigate shrinkage in alkali-activated binders.

Performance of self-healing mortar containing bacteria immobilized in alginate coated alkali activated lightweight aggregate

Among possible bacteria carriers available on the market, lightweight aggregate (LWA) shows great potential, as it is compatible with the mortar matrix and can retain high amounts of bacteria in the pores. However, the high energy needs to produce commercial LWA is a point of consideration in terms of producing sustainable mortar. Furthermore, the need of increasing the use of fly ash in countries, such as Indonesia, that rely for their electricity on coal power plants is still high. Therefore, LWA generated by cold bonding of fly ash was introduced here as an alternative bacteria carrier. Due to the high open porosity, a coating is needed to protect the bacteria and prevent leakage. Sodium alginate was applied as a coating on expanded clay and fly-ash based LWA containing cells or spores of Bacillus Sphaericus. The viability of spores and cells after encapsulation, and the compressive strength, the healing efficiency and the sealing efficiency of resulting mortar were investigated. The results show that the cells and spores of B. sphaericus are still viable and can actively decompose urea after encapsulation into both LWA types coated with sodium alginate. The strength decreased up to 11% in all mortar samples containing LWA coated with sodium alginate compared to mortar containing LWA without alginate coating. The sodium alginate coating improved the healing efficiency of mortar when cracks were created at 90 days. However high variability occurred for the sealing efficiency, due to the non-uniform crack geometry. In conclusion, fly ash based LWA as a bacterial carrier provides adequate healing performance, similar to commercial expanded clay, but slightly decreased the mechanical properties of resulting mortar.

Soft Computing Modeling Including Artificial Neural Network, Non-linear, and Linear Regression Models to Predict the Compressive Strength of Sustainable Mortar Modified with Palm Oil Fuel Ash

Producing sustainable concrete and mortar is the idea that have been investigated by many researchers in the world through using waste materials in the mortar or concrete compositions to reduce the thread on the environment. In order to predict the compressive strength of mortar, this article proposes statistical models utilising linear regression (LR), nonlinear regression (NLR), and artificial neural network (ANN) based on experimental data collected from prior research in the field. The pozzolanic material used in mortar is agricultural waste, specifically Palm Oil Fuel Ash (POFA). In order to choose the most efficient model, the proposed models were evaluated using several statistical parameters. When compared to alternative models (Linear regression, nonlinear regression, and ANN), the one developed using ANN proved to be the most efficient in terms of approach, giving lower values for root mean square error (RMSE) and mean absolute error (MAE) which were 5.11, and 4.175 respectively. The suggested ANN model performed well according to the scatter index (SI), and the coefficient of determination value (R2) value was 34% more than the R2 in the LR model and 23% greater in the NLR model.

Experimental investigations on sustainable mortar containing recycled seashell powder as cement partial replacement

Creating sustainable mortar containing recycled seashells is an innovative approach that can contribute to environmental conservation and reduce waste. The use of seashells as a partial replacement for traditional raw materials in mortar can have several benefits, including conservation of natural resources, waste reduction, and improved material properties. The current study uses Marsh Clam seashells after crushing the cleaned seashells into powder. Heated ( up to 600C°) and unheated seashells were considered in the experimental investigation. In both batches, a seashell powder (heated and unheated) was replaced with OPC cement in proportions of 6, 9 and 12% in the mixing process. XRD, SEM, EDS and mechanical tests were employed to determine the crystal structure and to provide a comprehensive understanding of the physical, chemical, and structural characteristics of the substance. The study concluded that the calcium carbonate (CaCO3) that is nature chemical form of seashells was turned to calcium oxide (CaO) during the heating process and the resulted product was highly reactive with water, improved microstructural properties of the concrete. It also promotes better particle packing, reduce porosity, and create a denser, more uniform concrete matrix and enhancing the overall performance of the material.

Application of machine learning boosting and bagging methods to predict compressive and flexural strength of marble cement mortar

Compressive (CS) and flexural strength (FS) of sustainable mortar made from waste materials were estimated using machine learning (ML) tools. Ensemble ML techniques, including extreme gradient boosting (XGB) and bagging regressor (BR), were utilized to accomplish the study goals. The outcomes of the estimation models were compared with target values, and statistical checks were performed to assess and compare the models. Additionally, in order to determine the influence of mortar constituents on CS and FS estimation of mortar, the Shapley Additive exPlanations (SHAP) method was implemented. XGB exhibited superior predictive capabilities for the CS and FS of mortar compared to the BR approach, as evidenced by R2 values of 0.98 and 0.94 for the CS-XGB and FS-XGB models, respectively. Statistical validation checks provided additional evidence that the ML models were effective in estimating the strength of sustainable mortar. The results of the SHAP study showed that the most promising components that contributed favorably to strength were testing age, fly ash, and rice husk ash; however, waste-derived cement had a negative impact. Establishing models that can determine the CS and FS of mortar for different values of the input parameters could save time and money compared to doing the tests in a lab.

Sustainable Mortars with Slag for Green Facades

Sustainable Mortars with Slag for Green Facades

Performance of sustainable mortars containing blast furnace slag and fine concrete waste: an environmental perspective

Performance of sustainable mortars containing blast furnace slag and fine concrete waste: an environmental perspective

Experimental Study on the Durability Performance of Sustainable Mortar with Partial Replacement of Natural Aggregates by Fiber-Reinforced Agricultural Waste Walnut Shells

Through the recovery and reuse of agricultural waste, the extraction and consumption of natural aggregates can be reduced to realize the sustainable development of the construction industry. Therefore, this paper utilizes the inexpensive, surplus, clean, and environmentally friendly waste agricultural material walnut shell to partially replace the fine aggregates in mortar to prepare environmentally friendly mortar. Considering the decrease in mortar performance after mixing walnut shells, basalt fibers of different lengths (3 mm, 6 mm, and 9 mm) and different dosages (0.1%, 0.2%, and 0.3%) were mixed in the mortar. The reinforcing effect of basalt fibers on walnut shell mortar was investigated by mechanical property tests, impact resistance tests, and freeze–thaw cycle tests. The damage prediction model was established based on the Weibull model and gray model (GM (1,1) model), and the model accuracy was analyzed. The experimental results showed that after adding basalt fibers, the compressive strength, split tensile strength, and flexural strength of the specimens with a length of 6 mm and a doping amount of 0.2% increased by 13.98%, 48.15%, and 43.75%, respectively, and the fibers effectively improved the defects inside the walnut shell mortar. The R²s in the Weibull model were greater than 87.38%, and the average relative error between the predicted life of the impacts and the measured values was greater than 87.38%. The average relative errors in the GM (1,1) model ranged from 0.81% to 2.19%, and the accuracy analyses were all of the first order.

Sustainable mortars and plasters from an industrial point of view

Sustainability has many facets. We will give insight into the development of sustainable mortars and renders using recycled limestone which attributes to the demand to increasingly replace raw materials from natural resources by recycled materials. Furthermore, we will present newly developed renders with improved thermal insulation properties as a necessity to keep heating energy in our buildings. All along the way, synergies are used by combining findings from university research projects, improvements of the raw materials industry und progress in the dry-mix mortar industry.

Impact of Physico-Chemical Characteristics on the Mechanical Strength and Pore Structure of Air Lime Mortars with Isparta Tuff and Banahmeta Additives

The physical and chemical interactions between the lime and pozzolans in conservation mortars are fundamental to sustainable building practices. Here, we report experimental investigations on pure air lime mortar, air lime-isparta tuff mortar, and air lime-banahmeta mortar. Isparta Tuff is formed from volcanic rocks found in the Southwest between Isparta and Burdur city centres in Anatolia, belonging to the Gölcük volcanism. The microstructural and physiochemical interactions of these mixed designs were investigated. Importantly, this study quantifies critical performance parameters of air lime mortars incorporating Isparta tuff as a pozzolan. It supports using local and natural volcanic tuffs in developing sustainable mortars for the conservation of historical assets in Turkey.

Durability Assessment of Sustainable Mortar by Incorporating the Combination of Solid Wastes: An Experimental Study

The excessive mining of high-quality river sand for cement sand mortar resulted in environmental impacts and ecological imbalances. The present study aims to produce sustainable mortar by combining solid waste such as desert sand, stone dust, and crumb rubber to fully replace river sand. In addition, replacing cement with silica fume helps reduce the environmental carbon footprint. The present research prepared three types of mortar mixes: natural dune sand mortar (M1), natural dune sand stone dust crumb rubber mortar (M2), and natural dune sand stone dust crumb rubber silica fume mortar (M3). The developed mortar samples were examined at ambient and elevated temperatures of 100°C, 200°C, and 300°C for 120 minutes. Furthermore, 3 cycles of 12 hours each at freezing temperature (-10° ± 2°C) and crushed ice cooling (0° to -5°C) were also tested. Results of the study showed an increment in compressive strength values in M1, M2, and M3 mortar mixes (up to 200°C). Later, an abrupt drop in the compressive strength was noticed at 300°C in all mixes M1, M2, and M3, respectively. The mix M3 combinations resist heating impacts and perform significantly better than other mixes M1 and M2. Also, M3 combinations resist the cooling effect better than M1 and M2. It can be concluded that the mortar mix M3 with desert sand, stone dust, crumb rubber, and silica fume combination is considered the best mix for both heating and cooling resistance. Hence, the developed sustainable mortar M3 combination can be utilized in all adverse weather conditions. Doi: 10.28991/CEJ-2023-09-11-09 Full Text: PDF

Experimental Investigation on Using Electrical Cable Waste as Fine Aggregate and Reinforcing Fiber in Sustainable Mortar

Experimental Investigation on Using Electrical Cable Waste as Fine Aggregate and Reinforcing Fiber in Sustainable Mortar