Experimental Study On Flexural Performance Of Mixed Aggregate Concrete

The combined aggregate concrete is a transitional concrete that aims to overcome the shortcomings of traditional concrete. Compared to traditional concrete, it features lighter weight and better durability. While compared with the lightweight aggregate concrete, it has higher specific strength, stronger modulus of elasticity and smaller shrinkage deformation and creep deformation. Based on these features, the combined aggregate concrete is used in some engineering projects, such as large-span bridges, super-high buildings, and marine constructions. This paper focuses on the fracture resistance of combined aggregate concrete, aiming at helping readers to have a better knowledge of mechanical property parameters, which in return can make them serve better for practical engineering.According to different water cement ratio, lightweight aggregate replacing rate and lightweight aggregate types,48groups of concrete test blocks are made to test its cube compressive strength, frac ture resistance and its property of bending stress and strain. After studing the relationship among wat er cement ratio, lightweight aggregate replacing rate, lightweight aggregate types and their effects on the fracture resistance of combined aggregate concrete, we have made following conclusions:(1)With the replacing rate of lightweight aggregate increasing, the fracture resistance of combined aggregate concrete gradually decreases. The water-cement ratio have a little influence on combined aggregate concrete flexural strength.(2) The ratio of Shale ceramsite combined aggregate concrete Flexural Strength and compressive strength is between1/9-1/17;The ratio of clay ceramsite combined aggregate concrete flexural strength and compressive strength is between1/12-1/10.(3) Equal strength grade of concrete, the flexural strength is larger than the axis tensile strength about10%, is bigger than its split tensile strength is about4%(4)Water cement ratio and ceramsite replace rate have a little influence on combined aggregate concrete flexural strength ultimate strain. The influencen of lightweight aggregate replacing rate about combined aggregate concrete flexural peak strain is greater than the influencen of water-cement ratio on it.(5) Put forward the combined aggregate concrete flexural elastic modulus and flexural strength and the relation between bulk density.