Non-biodegradable aggregate prepared from low density polyethylene (LDPE) plastic was used as partial replacement for sand in cement mortar. Various volumetric fractions of 0, 5, 10, 20, 30, 40, 50, and 60% sand were replaced using ground LDPE waste plastic. Mortar mixtures of 1:3 cement to fine aggregate were prepared at various water/cement ratios of 0.45, 0.50, 0.55 and 0.60, then used to cast 50 mm cubes and 40 × 40 × 160 mm prisms. It was found that strength reduces significantly as the proportion of LDPE in mortar increases, however, mixtures containing 50–60% LDPE satisfy the strength criteria for masonry mortars. Based on experimental data, a model was proposed for predicting the compressive strength of mortars containing waste plastics. The model’s validation gave generally accurate predictions for the strengths of mortars made using different types of plastics.

Every year, a massive amount of natural materials are subjected to high temperatures during cement production, resulting in 5% to 8% of total global carbon dioxide (CO₂) emissions. The employment of supplementary cementitious materials (SCMs) for developing construction materials could reduce the use of natural materials and CO₂ emissions during cement manufacturing. One option to accomplish this is to examine the possibility of producing masonry mortars using thermally treated waste concrete powder (WCP) and ground granulated blast furnace slag (GGBFS). The main objective of the present study is based on this. The study was conducted in two phases. In Phase I, WCP was thermally treated at various temperatures of 0 °C, 300 °C, 500 °C, and 700 °C and then used to prepare mortars at a binder-to-fine aggregate ratio of 1:3. From the strength results obtained in Phase I, a mortar mixture made with 500 °C WCP was selected for Phase II investigation. Mortars were produced by replacing the 500 °C WCP with GGBFS at 0%, 25%, 40%, 60%, 70%, and 85%. It was found that the performance of the mortars was enhanced when GGBFS was used up to 60%. The mortar mixture containing 60% thermally treated WCP and 40% GGBFS produced the optimal physical and mechanical properties. Also, material characterization was carried out on the binders using X-ray fluorescence, scanning electron microscopy, and thermogravimetric analysis. The results indicate that the thermally treated WCPs and GGBFS contain oxides similar to cement, making them suitable for mortar production. In conclusion, the study has shown the feasibility of producing masonry mortars using thermally treated WCP and GGBFS.

In recent years, waste concrete powder (WCP) has emerged as a possible substitute for ordinary Portland cement (OPC), addressing concerns related to emissions of carbon dioxide (CO₂) and solid waste handling. However, there is limited information on the trends in WCP related studies. This research attempts to investigate the current bibliometric state of WCP studies over the past 15 years. The Scopus database and the program VOSviewer were used for the retrieval of bibliometric data and graphic representation of networks. In total, 86 articles were used for the study. The Journal of Construction and Building Materials emerged as the leading source, with 27 publications and 451 citations. China ranks as the most productive country, contributing 63 publications and receiving 1372 citations. South Korea follows with 9 publications and 151 citations. It was revealed that WCP research has demonstrated steady growth, starting with just two publications in 2017 and increasing to 34 by 2024. Also, this study systematically reviewed important literature to explore various research areas related to WCP studies. It was found that WCP studies have been examined from approximately thirteen distinct perspectives. In conclusion, this study offers valuable insights into the evolution, focus areas, and global distribution of WCP research. For practitioners, the findings highlight emerging opportunities to incorporate WCP as a sustainable material in construction, supporting resource efficiency, cost reduction, and alignment with circular economy goals.

Waste concrete powder (WCP), obtained from discarded concrete, was used as a fractional substitute for cement in mortar production. During mortar preparation, cement was partially replaced with WCP at intervals of 10%, ranging from 0 to 30%. The obtained results showed that increasing the WCP level led to a considerable reduction in mechanical properties of the mortars. For instance, replacing 30% of the cement with WCP led to a reduction in the control mortar’s compressive strength from 40 N/mm² to 30 N/mm² over a 28-day period. However, the mortars still met the strength required for masonry applications. Also, predictive models were developed using the experimental data to estimate the compressive and flexural strengths of WCP mortars. The developed models’ effectiveness was assessed using experimental data gathered from published studies. The proposed models make it feasible to change conventional mortars’ standard strength grades into equivalent values for WCP-based mortars. Hence, the models can be effectively applied for practical predictions, as well as for the design and analysis of sustainable mortars incorporating WCP.

1. Concrete remains the most widely used construction material worldwide owing to its versatility, the widespread availability of its constituent materials, and its favourable mechanical performanc...

The use of sustainable materials in construction is essential for reducing environmental impact and optimizing costs. This study examines the effect of incorporating recycled sand and ground granulated blast furnace slag (GGBFS) on the performance of mortars. Experimental tests were conducted to evaluate the density, compressive strength, and flexural strength of the mortars. Also, comparative cost and environmental impact analyses were performed to determine the feasibility of these alternative materials. The results indicate that while higher proportions of recycled sand reduce mortar strength, the inclusion of GGBFS helps enhance the overall performance. For instance, replacing 40% of the cement with GGBFS increased the 28-day compressive strength of the mortar mixture comprising 100% cement, 80% natural sand, and 20% recycled sand from 33.2 to 35.7 MPa. Additionally, the combined use of recycled sand and GGBFS significantly lowers production costs and carbon emissions compared to conventional mortars. This research highlights the potential of these materials in developing sustainable and cost-effective mortars, promoting resource efficiency and reducing the environmental footprint of construction practices.