Concrete Tensile Strength Test Using Different Sand Gradation Zones t o Mitigate Earthquake Buildings

Abstract

Sand is one of the building materials forming the concrete mass. Sand has a type based on quarry sources, namely sea sand, river sand and mountain sand. Sand has different characteristics such as gradations (grain fineness), unit weight, mud content. Based on the SK-SNI 03-2834-1993 standard, sand has a grain size which is classified as very rough, rough, medium, smooth and very smooth. Sand that has a good gradation is separated in the form of a graph as zones 1 to 4. Concrete has good compressive strength but is weak on tensile strength. To increase the tensile strength, fiber can be added. The use of wire fiber is expected to increase the performance of buildings in earthquake-prone areas. In this study the fiber used was metal wire with a length of approximately 2 cm, designed compressive strength of concrete of 25 MPa, with a cylindrical sample diameter of 15cm and a height of 30cm, 3 month old age split tensile strength test was conducted, by using sea and mountain river sand with different zones. The results obtained that the division of the sand zone into rough to fine classification does not provide a significant trend for the tensile strength of the concrete. Mechanically, the addition of wire fibers for Air Lakok sand, Lubuk Kebur river sand and Penanding river sand has decreased the tensile strength. While the sea sand of Selubuk, the river sand of Talang Rasau and the mountain sand has increased tensile strength. Visually, all concrete that is given wire fiber has better ductility, where the concrete does not experience brittle cracks and the elements are still bound to each other.