Experimental Research On Shrinkage Of Concrete

Shrinkage is the inherent physical properties of concrete. When concrete is bound, the shrinkage will lead to concrete shrinkage stress. The concrete cracks if the stress exceeds the tensile strength of concrete. Cracks have a great influence on the durability of concrete. Reduce the shrinkage can control the cracks of the concrete. Concrete shrinkage in natural state is a superposition of different shrinkage, this article discusses the different types of shrinkage and the mechanism of shrinkage. Through the concrete shrinkage test of fly ash, slag, sand, UEA expansive agent and polypropylene fiber, shrinkage and compressive strength are analyzed. Simultaneously the influence of combinations of fiber and expansion agent on concrete shrinkage is discussed.It is shown that the fly ash can reduce shrinkage within a certain content, as the dosage increased, shrinkage decreased, mineral powder on the contraction is more complex. In a certain dosage range, slag can increase the concrete shrinkage. As the dosage continues to increase, the slag can reduce the shrinkage of concrete. The sand has adverse effects of concrete shrinkage. The fly ash and the slag can reduce the compressive strength of concrete. The UEA expansive agent and the polypropylene fibers can reduce shrinkage but have not significant effect on concrete compressive strength.