Improvement of Earth into Concrete as an Eco-friendly Building Material – Effect of Soil Gradation and Chemical Admixtures

Environmental concerns and economic crises have been more critical in recent years, making it impossible to continue construction using traditional resources (cement, sand, and natural aggregates) in the same way as before. However, the use of earth is a cost-effective solution and it can enhance the sustainability of construction materials by employing soil as a building material. This study evaluated soil consistency that would be acceptable to make soil concrete and analysed the effect of chemical admixtures in achieving the maximum possible strength. Hence, the study suggested the possibility of using soil to form concrete as a replacement for cement concrete to the maximum extent with self-compacting properties. The soil was used to produce the concrete, stabilizing with cement and chemical admixtures were used to improve the strength and workability. According to the experimental investigation, it can be concluded that soil can be used as concrete with a characteristic strength of 15 MPa. The recommended native soil consistency for soil concrete should be developed by rearranging the native soil gradation to 5%–10% fines, 55%–71% sand, and 24%–40% gravel. The recommended cement amount as the stabilizer is 16% to 18% of the weight of the improved dry soil mixture. The strength and workability can be further improved by employing suitable chemical admixtures. Finally, this extensive study concluded that soil could be used to produce concrete for the construction industry through applications with minor improvements to the existing soil.