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The objective of this study is to explore the feasibility of developing environmentally friendly green roller-compacted concrete (RCC) by utilizing locally available materials. The research investigates the behavior of RCC properties when different amounts of solid waste materials (brick powder, glass powder, and steel slag) are added as substitutes for cement content. To accomplish this, four laboratory tests were conducted: compressive strength, flexural strength, X-ray diffraction analysis, and scanning electron microscope imaging. These tests aimed to identify the changes in concrete properties resulting from the inclusion of waste construction materials as cement replacements. The study employed an approach that involved adding waste materials to the concrete mixture, with replacement percentages ranging from 10.0 to 40.0% in increments of 10.0%. Consequently, 12 concrete mixtures were prepared to examine the effects of adding waste materials (10.0–40.0%) as substitutes for cement content. In addition, one reference mixture was designed without any inclusion of waste materials for comparison purposes. In general, the results indicate that as the percentage of waste construction materials increases in the mixtures, there is a corresponding decrease in compressive strength. However, it is noteworthy that the strength activity index (SAI) exceeded 75% according to ASTM C618 standards. This indicates that the waste construction materials possess pozzolanic properties, making them suitable for use as cement replacements in RCC mixtures.

This study determined the influences of Bacillus sphaericus Laboratorium voor Microbiologie Gent (LMG) 22257 bacteria activity on mortar samples cured in various media regarding compressive strength, porosity, water absorption, and water permeability. Three types of curing media were utilized, namely distilled water (D.W.), deposition water (D.M.), and run-off water (R.W.). The compressive strength was measured using 100 mm mortar cubes. The water porosity, water absorption, and water permeability were analyzed using the Leeds permeability cell with dimensions of the mortar cylindrical specimens of 55 mm diameter and 40 mm thickness. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX) were utilized, respectively, for microstructure analysis and quantifying the elements with atomic numbers. The results indicated the presence of calcium carbonate and more calcium silicate hydrate (CSH) depositions on bacterial mortars. The inclusion of Bacillus sphaericus LMG 22257 bacteria activity and curing media type affected mortar properties through compressive strength and durability improvements, as well as the reduction in water porosity, water absorption, and water permeability of mortar. The comparison of CaCO3 precipitation, such as a sufficient growth nutrient requirement and hostile bacteria environment, was observed. Curing in R.W. produced the most significant bio-based cement (BBC) mortar improvement, followed by D.M. BBC curing in runoff water had a 40% improvement in strength compared to normal curing. As a conclusion, runoff water is a highly promising sufficient nutrient to bacteria for the biomineralization process to produce CaCO3. This work also aims to apply this approach in the field, especially in sewerage and drainage systems. [ABSTRACT FROM AUTHOR]