Comparative Study on the Impact of Sand and Lime on the Physical and Mechanical Characteristics of Unfired and Fired Earth Bricks

Earth bricks represent one of the most important and widely used building materials in current era, due to its unique physical and mechanical properties compared to other materials. Earth bricks are available in two main types: raw earth bricks and fired bricks. The physical and mechanical properties differ for each type, which affects their performance in various applications and their long-term durability. Several studies have been conducted to improve the properties of raw and fired bricks and address their weaknesses. In this research, we aim to investigate the effects of adding dune sand and lime on the physical and mechanical properties of raw earth and fired bricks, and compare the results. Sand was added by 25%, while lime was added by 0, 6, 8, 10, and 12% of the soil matrix weight. Initially, we determined the properties of the raw materials used. After creating the samples, they underwent tests for bulk density, longitudinal shrinkage, compressive strength, and flexural strength. The study revealed the positive impact of adding sand on the physical and mechanical properties of raw and fired bricks. It contributed to reducing the bulk density and longitudinal shrinkage of the samples, while increasing their compressive and flexural strength to varying extents. The results also showed the positive effect of lime on the physical and mechanical properties of raw bricks, as long as it was added at a ratio not exceeding 10%. However, the addition of lime to fired bricks affected the physical properties positively but it has a negative effect on the mechanical properties.