Waste from construction and demolition (also known as CDW) is one of the most harmful environmental issues. This study's primary goal is to produce new mortar and brick materials from recycled concrete powder (RCP) and recycled brick powder (RBP), two of the most popular CDW. Geopolymeric mortar and brick samples were produced by passing RCP and RBP through sieve No. 50 (with sand filler if necessary) and combining them with an alkaline solution made of water glass (WG) and NaOH. In this study, the mixture was then cured for three days at 80 °C in an oven. The effects of filler, RBP amount, WG amount, and the concentration of NaOH alkaline solution on the samples’ strength were examined. Additionally, XRF and SEM/XRD tests were performed to verify the materials' composition and microstructure. The mechanical strength of the samples showed an increase with the increase of RCP values, so the brick sample with filler showed the highest compressive strength, measuring 59.53 MPa. The study's samples exhibited strong mechanical properties. Additionally, all of the bricks' water absorption fell within the standard range. In summary, according to different standards, both waste concrete and waste brick can be used to produce geopolymer materials especially bricks for construction and paving purposes.

Sodium chloride (NaCl), commonly known as salt, is a substance that is utilized in a variety of businesses, including the tourism and construction industries. Therefore, the main purpose of this article is to accommodate a salt-based building material called NaCl-binder for tourist and industrial applications. By utilizing salt mortar with varying grain sizes, food-grade corn starch as an exclusive binder agent (without using any non-starch binder), and water under microwave-cured conditions, environmentally friendly hydrophobic hybrid NaCl-binder samples with low bulk density were successfully produced. The fabrication of these samples involved an inventive utilization of small quantities of starch. This study evaluated the impact of microwave exposure time on the strength of salt samples, particle interconnectivity and chemical composition using SEM, XRD, and XRF analyses. The compressive strength of the samples showed a remarkable increase, with a 600% improvement when using 0 to 1% corn starch, and a 137% increment when using 1 to 10% corn starch, indicating a lower rate of increment with higher starch consumption. A key aspect of this research is the significant reduction in starch consumption compared to other corn starch-based materials during the manufacturing process of the incorporated materials, highlighting its novelty and importance.

Aims Microbial induced calcium carbonate precipitation (MICP) is one of the bio‐cementation methods for improving granular soils. This study evaluate the feasibility of obtaining a bacterial solution with high optical density and urease activity by an inexpensive corn steep liquor (CSL) medium in non‐sterile conditions in order to achieve sand improvement. Methods and Results Corn steep liquor media with different concentrations (different dilution rates) were prepared and, without any autoclaving (non‐sterile conditions), different percentage of the inoculum solutions were added to them and incubated. Effect of inoculum solution percentage and CSL dilution rates on specifications of bacterial solution was evaluated. Urease activity and scanning electron microscope (SEM) and X‐Ray Diffraction (XRD) were used to efficiency of CLS media in sand improvement. The considerable urease activity was measured as 5·7 mS cm⁻¹ min⁻¹ using nonsterile CLS. By using CYNU (CSL‐Yeast extract‐NH4Cl‐Urea) bacterial solution, the urease activity of 5·5 mS cm⁻¹ min⁻¹ for the OD₆₀₀ (optical density at 600 nm) of 1·88 and, consequently, specific urease activity of 2·93 mS cm⁻¹ min⁻¹ OD₆₀₀⁻¹ was obtained. The highest unconfined compressive strength (811 kPa) was obtained for the CYNU. XRD revealed new calcite peaks next to the quartz peaks. Conclusions Production of inexpensive bacterial solution using diluted CSL as the inexpensive, effective and powerful culture media for Sporosarcina pasteurii cultivation in nonsterile conditions, allows geotechnical and biotechnological engineers to use MICP technology more widely in land improvement and field‐scale bio‐cementation and bioremediation projects. Significance and Impact of the Study Obtaining high urease activity of inexpensive microbial solution using diluted CSL as the culture medium in nonsterile conditions, as the unique results of this study, can be significant in the field of bioremediation studies using MICP.