Strength improvement of early age unfired soil lime bricks

Despite their low performance quality and aesthetics, non-standard bricks are commonly used in the construction of low-rise buildings and rural houses in Indonesia. These bricks are produced traditionnally in home run plants with little adherance to appropriate mix designs. These unfired soil lime bricks enter the market within 2 weeks of production, which inflicts potential loss to the buyers due to their low performance quality. The paper discusses strength improvements of these early age bricks through 2 methods. The first method is by adding the optimal amount of mixing water to the soil and lime mix. The second method is by adding untreated coconut fibers with a 2.5 cm fiber length as additional reinforcements. The effect of 3%, 5% and 7% fiber addition to the mechanical properties of bricks were investigated. Laboratory tests showed that higher compressive strengths, compared to that of traditional unfired soil lime bricks, could be achieved through the 2 proposed methods. The bricks reinforced with higher percentage of untreated coconut fibers have better modulus of ruptures.