Assessment of the feasibility of using sisal fiber reinforced cement Mortar with termite clay soil for roofing tiles

Abstract

There is need to provide alternative materials that are locally available, that can reverse the adverse environmental effects caused by excessive use of Portland cement. It is important to have materials with low energy demand and low cost. The overall objective of this research was to assess the suitability of sisal fiber reinforced cement mortar with termite clay soil partial replacement for cement for use in roofing tile for housing. Termite Clay Soil (TCS) was obtained from Nduru Village, Usigu Sub Location, Siaya County in Kenya. The TCS used in this research was uncalcined. Chemical analysis on TCS was carried out by use of Energy Dispersive X ray diffraction (EDXRD), which is an analytical technique for characterizing materials. The sum of SiO2, Al2O3, and Fe2O3 was found to be 93%, which is greater than 70% required as stipulated by the ASTM C 618 (1980). The pH of TCS was determined using pH meter and found to be 5.21. TCS replacement levels of 0, 10, 20, 30 and 40% by weight of cement was carried out to determine setting times, compressive strength, flexural strength and absorption rate of the resulting blended cement, from which optimal replacement value was obtained. 10% optimal replacement level achieved was used to determine the engineering properties of mortar namely compressive strength, flexural strength and absorption with sisal fiber reinforcement (SFR) of 0, 0.5, 1.0, 1.5 and 2.0% by weight of cement and fiber length of 25mm. Other studies have established that 25 mm length is optimal and this research adopted this length without further studies. The optimal replacement level for TCS was found to be 10% for cement achieving compressive strength of 44.9 N/mm2, flexural strength of 6.5 N/mm2 and 6.5 % absorption rate which satisfied the requirement of KS EAS 18-1:2001 of minimum of 42.5 N/mm2 for 42.5N Cement. Up to 2 % sisal fiber reinforcement satisfied the requirement of KS 02-444: 1984 of minimum 2.80 N/mm2 for flexural strength and maximum 10% for absorption rate. Residual impact strength ratio (Irs) of sisal fiber reinforced cement mortar with sisal fiber reinforcement for cement at percentages of 0, 0.5, 1.0, 1.5 and 2.0% increased with increase in reinforcement and at 2%, it yielded a value of 3.00. It was concluded that TCS was pozzolanic with the sum of SiO2, Al2O3 and Fe2O3 equals to 93% and its pH was 5.21 which is acidic and therefore suitable for reducing the alkalinity of the cement matrix and hence reduction in embrittlement of sisal fibers. The optimal replacement of TCS was 10% for cement with up to 2% sisal fiber reinforcement for use in roofing tiles. Since Irs is closely related to Coefficient of restitution (CoR), this value satisfied the requirement of BS EN 14411: 2012, which recommends a minimum value of 0.55 for tiles intended for floors with low mechanical requirements. No standard was available that specifies the impact energy and impact residual strength ratio for roofing tiles and therefore this research adopted the standard for floors. From the cost analysis, cost per square meter of sisal fiber reinforced cement mortar with termite clay soil partial replacement tile was found to be Ksh 240, which is cheaper than other roofing materials which are in the range of 300 to Ksh 2000. There are also associated benefits which include: reduction of alkalinity of the cement media and therefore preservation of sisal fibers in the matrix; reduction in the emission of greenhouse gases by partial replacement of cement with the pozzolanic material and low energy consumption. Further studies are recommended on uncalcined termite clay soil as partial replacement for cement for use in roofing tiles.