Jeon, et al (2024) Engineering performances of permeable concrete blocks using oyster shell, bottom ashAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More, and biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2024.137374

A recent study investigated the use of oyster shell, bottom ash, and biochar in the development of permeable concrete blocks. These materials were chosen for their potential to recycle industrial by-products and their effects on the engineering performance of the blocks. The study found that the flexural strength of the blocks decreased with higher bottom ash content, while the inclusion of oyster shell and biochar increased the 28-day flexural strength and accelerated the development of initial strength. The permeability of these blocks was significantly higher than the Korean standard, with measurements ranging from 41.6 to 102.9 times greater.

Oyster shell cement and biochar were found to reduce permeability, whereas bottom ash increased it. The porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More of the specimens increased with more bottom ash and less oyster shell cement, while the addition of biochar reduced continuous porosity. The study concluded that the oyster shell cement could replace up to 40% of conventional cement, and bottom ash aggregate could replace up to 20%. A 2% biochar mixture allowed the blocks to meet the flexural strength requirements for sidewalks even with high replacement ratios of oyster shell and bottom ash.

This research highlights the potential for using these industrial by-products to create environmentally friendly permeable concrete blocks, contributing to sustainable construction practices while meeting necessary engineering standards.