American Journal of Physical Chemistry 2014; 3(2): 9-14 Published online April 30, 2014 (http://www.sciencepublishinggroup.com/j/ajpc) doi: 10.11648/j.ajpc.20140302.11 The effect of mixing rice husk ash and palm oil boiler ash on concrete strength Karya Sinulingga 1 , Harry Agusnar 2 , Basuki Wirjosentono 2 , Zakaria Mohd. Amin 3 1 Department of Physics Education, Faculty of Mathematics and Natural Science, State University of Medan, Indonesia 2 Faculty of Mathematics and Natural Sciences, North Sumatera University, Medan Indonesia 3 School of Materials and Mineral Resources Engineering, Engineering Campus, University Sains Malaysia, Nibong tebal, Penang Email address: Karyasinulingga.2014@gmail.com (K. Sinulingga) To cite this article: Karya Sinulingga, Harry Agusnar, Basuki Wirjosentono, Zakaria Mohd. Amin. The Effect of Mixing Rice Husk Ash and Palm Oil Boiler Ash on Concrete Strength. American Journal of Physical Chemistry. Vol. 3, No. 2, 2014, pp. 9-14. doi: 10.11648/j.ajpc.20140302.11 Abstract: Physical properties such as compressive strength and tensile strength of concrete can be changed by adding a mixture of rice husk ash and palm oil boiler ash in concrete. The rate of absorption of water by the concrete mixed with rice husk ash and mixed with palm oil boiler ash was further tested. Levels addition of the mixture to be tested is 5%, 10%, 15% , and 20% by long immersion for 7 days, 14 days, 21 days, 28 days, and 60 days. Tests on the compressive strength and modulus of elasticity of concrete from a wide variation in the mixture, analyzed by XRD (X - ray diffractometry). Analysis of the surface morphology and content of elements contained in the sample of natural bentonite, used Scanning Electron Microscopy (SEM). The test results showed the addition of a mixture of rice husk ash, palm oil boiler ash , and the addition of a mixture of both, ideal on concrete that has the addition of a mixture of 5% composition. With the addition of the concrete mix results in a SiO 2 content of the concrete is reduced. Significant content of SiO 2 is with a mixture of 5% rice husk ash. Compressive strength and modulus of elasticity of concrete with rice husk ash mixture 5% higher than the others. Keywords: Concrete, Compressive Strength, Modulus of Elasticity 1. Introduction Concrete is a building material that is most widely used in the world. Global production is around 4 billion m 3 annually, with about 1.25 billion tons of cement a year [1]. Concrete is a mixture of fine and coarse aggregate cement, sand and water, in the presence of air cavities. As the composite material properties of concrete is very dependent on the interaction between the constituent materials. Cement is the key ingredient in concrete, although there were only 7-15% of the mixture. The use of partial cement replacement material through an innovative mix composition will reduce the amount of cement used in order to reduce greenhouse gas emissions and use of fossil energy consumption of the earth in the cement industry [2]. The use of adhesive or ceramic or inorganic matrix for natural fibers, developed in various countries including the use of natural fiber rice husk ash and palm oil boiler ash. Mortar that use palm oil boiler ash as a partial replacement of cement, showed that the maximum compressive strength obtained in the palm of boiler ash content between 20% - 30% [3]. Rice Husk Ash fiber properties can reduce the density of the concrete making it possible to make a lightweight concrete [4]. Rice husk ash is a residue of agricultural rice milling process. Indonesian Central Bureau of Statistics ( 2011) reports that paddy production in 2011 by 1 st Forecast Figures (FF I) - 2011 is estimated at 67.31 million tons of paddy rose 895.86 thousand tons (1.35 percent) than in 2010 amounted to 66.41 million tons of paddy. Approximately 20 % of the total production of the resulting rice husk ash. This means that Indonesia produced 13,462 tonnes of rice husk ash in 2011. North Sumatra has oil palm plantations of about 855,333.00 hectares, with a total production of about 12,070,507.81 FFB (Fresh Fruit Bunches). With the palm oil boiler ash is formed in large quantities. Use of rice husk ash on cement composites can provide several advantages such as increased strength and endurance, reduce the cost of materials, reducing the environmental impact of waste materials, and reduce CO 2 emissions [5]. With the addition of palm oil boiler ash in a certain percentage of the weight