Effect of CaO content in Class C fly ash on the deformation properties of fully-graded concrete

In order to improve the capacity of resource application for the Class C fly ash, this paper investigates the effect of fly ash with different CaO contents on the deformation properties of fully-graded concrete. Fly ash with CaO content ranging from 0 to 22% was selected as a concrete admixture to study its soundness and the influence of its deformation properties such as ultimate tensile, elastic modulus, autogenous volume deformation and drying shrinkage in four-graded and three-graded concrete. The results showed that: the ultimate tensile strength and volume deformation of four-graded concrete were larger, while the elastic modulus and drying shrinkage were smaller than those of three-graded concrete; The CaO content of fly ash from 5.1 to 16.5% meets the requirement of soundness for concrete application, and the soundness is still qualified when the CaO content is 16.5% and the fly ash dosage is 70%. The ultimate tensile value and elastic modulus of concrete were proportional to the CaO content in fly ash, whereas the self-generated volume deformation was inversely proportional to the CaO content. The CaO content had little effect on the deformation performance.