The Use of Coal Waste in Concrete Construction & Survey of Compressive Strength

Document Type : Research Paper


1 Professor, Department of Civil Engineering, Tarbiat Modarres,Tehran, Iran

2 M.Sc Student, Department of Civil Engineering, Tarbiat Modarres,Tehran,Iran


Roller compacted concrete (RCC) pavement is one of the most economic and durable pavements which is used extensively in pavements with heavy traffic. The aim of this study is to investigate the feasibility of using wheat straw as fiber in order to change the behavior of RCC pavements and also to strengthen the RCC pavements. Cellulose fiber has proper effects on shrinkage cracks and toughness of RCC mixtures since it is of high tensile strength and low elastic modulus close to mortar. The Compatibility of fiber and concrete matrix and also the effects of straw on concrete components are discussed. The latter is to study if the straw can improve the features of the concrete or not. Natural fiber is a natural mixture with a cellulose structure. Different properties of cellulose, hemicelluloses and lignin, produce different layers. Polymer cellulose has glucose units and hemicelluloses are made up of different polysaccharide. Different types of fiber have different mixtures so it is expected that their behavior will be different in a cement matrix. Natural fiber is of low elastic modulus and high tensile strength and even their tensile strength is comparable to artificial types of fiber. Using special types of fiber such as steel fiber, which has a proper performance, is expensive, hence the basic aim of this study is to reinforce the concrete using cheap and accessible elements. Dry and saturated straw fiber with different aspects of ratio (30 to 150), different lengths and values, was added to RCC samples and VB test of  fresh complex and compressive strength test were made out of 15 x 30 cm, 28 days   samples and toughness testing of cylindrical 15*15 cm samples were applied. That set of these tests indicates the feasibility of using wheat straw at RCC as well as improved hardened concrete mixture toughness for 1 percentage of weight expressed in RCC mixture.