Durability of ‘Tulakan’ Soil as Natural Pozzolan to Substitute Portland Cement as Construction Material

Abstract

Tulakan soil containing compounds that needed in the formation of conventional cements, namely oxide compounds such as CaO, SiO2, Al2O3, and Fe2O3. Tulakan soil contains siliceous and aluminous materials which react with calcium hydroxide in the presence of water. Based on the composition of Tulakan soil, Tulakan soil in this study classified in the class N pozzolan. The amount of SiO2 + Al2O3 + Fe2O3 are more than 70% and SO3 content is less than 4% by weight (based on ASTM C618-92). Concrete mix design using SK-SNI-T- 15-1990-03. The ratio of Tulakan soil is vary at 10% ; 15% ; 20% ; 25% of Portland cement composition. The use of Tulakan soil as a partial replacement for cement can effectively maintain the compressive strength of concrete, it can even raise the value of compressive strength of concrete at a certain composition. A hundred concrete cylindric samples have been tested to study the concrete performance at two water cement ratio that are 0.4 and 0.5. Compressive strength of concrete with replacement of Tulakan soil + 10% of lime has a trend to increase and have a higher tendency to remain above the average of normal concrete. Overall, both for concrete with Tulakan soil or for concrete with Tulakan soil + lime are able to maintain even raise the value of compressive strength in concrete. As a result, the Tulakan soils effectively substitute the Portland cement, as it can increase the concrete compressive strength up to 3.24% on the percentage of Tulakan soil replacement of 10% – 20%. The split tensile strength test was able to raise up to 2.513% of normal concrete and the tension pullout bond test survive and rise up to 9.783% of the normal.