It was found that the ash content, alco hol-benzene solubili 1x NaoH solubility decreased by the reduction of the amount of impurities such as ash, resulting in a more stable, stronger and lighter fiber.Lignin starts to softe and dissolve at temperature over 70 °C, and acts as a binding agent for cellulose fibers.The pretreated(washed and boiled) fibers have higher lignin, holocellulose and alpha-cellulose contents than the unpretreated fibers. Thus, pretreated fibers are stiffer and tougher. Physical properties of fiber cement mortars The physical properties of the cement mortars were shown in Figs, 3-5.Test results showed that the cement mortar mixed with oil palm fiber has lower porosity and water absorption than those with coconut coir fiber, but the density are higher because the density of oil palm fiber is higher than that of coconut coir fiber, and this affects the bulk density of the cement mortar and also other factors.
Compressive strength of fiber cement mortars Test results of the compressive strengths of cement mortars are shown in Fig. 6 It was found that the compressive strengths of cement mortars
mixed with oil palm fiber and coconut coir fiber to decrease with an increase in the fiber replacement ratios.
Flexural strength of fiber cement flat sheets In accordance with ASTM C1185 and ASTMc1186. the results shows that the flexural strength of both fiber cement flat sheets with the fiber ratio of 10-15% had similar flexural strengths exceeding 4 MPa(or 40 kglcm in accordance with the ASTM c1186 standard. In addition, compared to previous researches the results are similar and consis- tent: ratios between 2% and 5% for both coconut coir fiber and oil palm fiber yielded the standardized flexural strength, in the case of roof sheets not manufactured by extrusion process with pressure. Thermal conductivity of fiber cement mortars The results of thermal properties of the cement mortars as shown in Fig. 8 demonstrate that as the ratios of both fibers increased, the thermal conductivity coefficient reduced to 66% compared to control cement mortar.