Analyze The Proportion of Volcanic Ash of Sinabung Volcano at The Most Optimum To Get The Compressive Strength and Tensile Strength of Concrete

The development of concrete as construction material is growing very rapidly followed by the needs of diverse communities. Based on the problems, we need knowledge and inovation to get a good quality concrete with low cost. In this study, volcanic ash of Mount Sinabung was chosen as an alternative material plus concrete filler. Materials derived from the bowels of the earth will be tested optimum levels that can be used to achieve the compressive strength and maximum tensile strength. The concrete to be tested is a concrete mixture design with fc '249 kg / cm2 (K-300). The concrete mix design was done by reducing the use of cement and the addition of volcanic ash of Mount Sinabung (0%, 10%, 15%, 20%). Compressive strength is tested when it’s 7, 14, and 28 days old. But, ultimate tensile strength is tested when it’s 28 days old. From the test result, we get optimum percentage with volcanic ash from Mount Sinabung is 10% with compressive strength 19.689 Mpa and ultimate tensile strength 1.348 Mpa. However, material is still worthy to use as concrete because it is compressive and ultimate tensile strength that almost reach normal compressive and ultimate tensile strength. Moreover, the using of material as admixture for concrete can be used as an alternative to save the environment from pollution