IJRRAS 8 (1) ● July 2011 www.arpapress.com/Volumes/Vol8Issue1/IJRRAS_8_1_08.pdf 57 PROPERTIES OF CONCRETE BLOCK CONTAINING RICE HUSK ASH SUBJECTED TO GIRHA Farah Alwani Wan Chik, * Badorul Hisham Abu Bakar, Megat Azmi Megat Johari & Ramadhansyah Putra Jaya School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang Seberang Perai Selatan, P. Pinang, MALAYSIA. Tel: +604-5996298, Fax: +604-5941009 * E-mail: cebad@eng.usm.my ABSTRACT Concrete blocks containing rice husk ash should be promoted as a new construction material to replace the existing blocks in market. Properties of the material used must be better understood first to obtain the desired concrete block. Generally, this paper presents a laboratory study on the effect of gasses incinerating rice husk ash (GIRHA) on properties of concrete block. The compressive strength, water absorption, moisture movement and modulus of elasticity were investigated. Preliminary analysis of the constituent materials of the ordinary Portland cement and Rice Husk Ash concrete blocks were conducted to confirm their suitability for block making. Physical test of the recently prepared mix was also carried out. 390mm x 190mm x 100mm concrete blocks were cast and compacted by a KANGO hammer for 7, 14, 28 and 60 days at 0, 10, 15 and 20 percent replacement levels. In conclusion, the high performance of masonry blocks can be produced using rice husk ash (RHA) as cement replacement material. The compressive strength of the OPC and RHA concrete blocks increases with age at curing and decreases as the percentage of RHA content increases. The study arrived at an optimum replacement level of 15%. Keywords: Concrete Blocks, Ordinary Portland cement (OPC), Rice Husk Ash (RHA), Compressive Strength 1. INTRODUCTION Rice husk which is also known as rice hull is a by-product of rice milling product. Demand for rice has increased due to population growth that exceeds 2.3% annually in Malaysia. In paddy milling operation, approximately 78% by weight is received as rice and the rest, about 22% as husk. The disposal of large bulk of husk has gain serious concerns due to the importance to preserve the environment in the present days. Open-field burning or uncontrolled combustion contributes to enormous environmental threats which lower the air quality in the area involved [1]. According to Ismail and Waliuddin [2], the un-burnt rice husk contained about 50% cellulose, 25-30% lignin and 15%-20% silica. Therefore, the presence of silica in this pozzolanic material makes possible the use of RHA to replace part of cement [2, 3]. In Malaysia, there is a lack of research conducted to improve the quality of concrete block available in the market. According to Gunduz [4] the production of concrete block has to meet the international standard that stipulates specific properties of the products. Primarily, they give little attention to the importance of quality assurance in properties of block namely strength, durability, weather resistance, insulating properties and fire resistance. In order to fulfill the criteria, all the stated properties will be explained in detail in the incoming chapter. Another study towards upbringing the development of innovative blocks production should be reviewed. Recent study shows that the utilization of by-products such as fly ash and other materials for example, sawdust and glass powder is frequently used in recent research instead of rice husk ash (RHA). It was found that RHA which is high in silica content can become potential cement replacement material Turgut and Murat Algin [5]. However, the objectives of this research are to study the effects of different replacement level of RHA on block unit properties and to determine the optimum RHA replacement level. 2. MATERIALS AND METHODS 2.1 Preparation of RHA In this study, rice husk had been used as a cement replacement material. Since this material is rich in silica, this leads to strength development due to pozzolanic reactions. Raw rice husks were obtained from a local paddy mill in Parit Buntar, Perak, Malaysia and then burnt at a temperature of 700ºC for six hours to obtain the ash via furnace gas. The RHA was ground using ball mill and the specific surface area of the RHA determined using BET nitrogen adsorption was found to be 11770m 2 /kg and the loss on Ignition (LOI) of the RHA was 3.03. The chemical compositions and physical properties of the RHA are tabulated in Table 1.