Experimental Study on Axial Tensile Stress-Strain Relationship of High Crack Resistance Concrete

Abstract

For demand of high crack resistance of concrete, the calcium-magnesium expansion agents and basalt fiber are chosen. The study of the full stress-strain curve of concrete under uniaxial tensile can comprehensively reflect its mechanical properties. The uniaxial stretch tests are used to study the concrete axial tensile constitutive model, and then the corresponding curve and formula are obtained in this paper. The influence of different dosages and water-binder ratio on the characteristic points of the curve is studied, and a suitable mathematical expression for the axial tensile stress-strain curve is proposed. Studies have shown that by adopting the method of dual admixture of expansive agent and basalt fiber, the toughness, tensile strength, ductility, and even other properties of concrete can be significantly improved. This shows that the dual admixture of the two materials has a strong toughening effect on concrete. With the amount of fiber content, the amount of expansion agent and the water-binder ratio is respectively 1%, 7% and 0.42, the performance of concrete shows the best state. The proposed calculation formula is in good agreement with the experimental results, which can provide a theoretical basis for the design and nonlinear analysis of concrete structures.