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.

Tests on the Indonesian coconut fiber showed that, compared to the results of previous studies, tensile strength and tension failure improved after the fiber was washed with water and dried. This study aims to obtain the effects of fiber length and fiber content on splitting tensile strength behavior of the concrete composite reinforced with coconut fiber. Experimental observations were carried out on the splitting tensile strength of coconut fibers as determined by the fiber content (1, 2, 3, and 4 % by a mass ratio of fiber per cement) and the length of the fibers (5, 20, 40 mm) in the concrete. The results show that a coconut fiber length of 5 mm and a fiber content of 3 % in fiber concrete composite gives the composite 1.28 times higher splitting tensile strength than plain concrete. The density of the fiber concrete composite decreases with the addition of coconut fiber content.

No abstract

The coconut fiber presents higher ductile properties than other natural fibers. In previous studies, it demonstrated than Indonesian coconut fibers presents an improved tensile strength and failure strain after washed with water and dried. The coconut fibers have the potential to reinforce material for construction, especially in earthquake areas such as tropical countries. The purpose of this research is to assess the benefit brought by coconut fibers content on the tensile behavior of mortar composite. Splitting tensile strengths were measured and microstructure observed using scanning electron microscopy (SEM). The influence of fiber content (expressed by a mass ratio fiber/cement) is investigated. The results show that a fiber content of 5% allows a 10 times higher deflection and presents a 1.5 times higher tensile strength than mortar without fiber. Further studies will focus on the bond strength between the fiber and the cement mortar matrix.

This study aims to assess the benefit brought by fibers content, and fiber length on the splitting tensile behavior of sugar palm fibers reinforced concrete composites. Three fiber lengths of 5, 20, and 40 mm in four-fiber content, namely 1%, 2%, 3%, and 4% by a mass ratio fiber per cement, were utilized in this investigation. The values of tensile strength and density are reported for ages up to 28 days. The result observes that the addition of sugar palm fibers increased the tensile strength of concrete and the density of sugar palm fiber in concrete decreases with the addition of sugar palm fiber. The mix of 1% fiber content and 20 mm length fiber gave higher tensile strength compared to other mixes.