Influence of Silica Fume and Zeolite on the Mid-Term Behavior of Expansive Self-Compacting Concrete

Self-compacting concrete is an innovation in the field of concrete that has resolved one of the main problems in the construction of concrete structures, namely the problem of concrete compaction. This type of concrete has caused a uniform composition in concrete with a new composition and the invention of superplasticizer. In the present study, the effect of introducing the additives of zeolite and micro silica and their replacement with a part of cement has been evaluated by testing the mechanical properties including compressive, tensile, flexural and ultrasonic waves tests on the control specimen of self-compacting concrete and expansive self-compacting concrete. Also, the short-term deformation due to shrinkage of self-compacting concrete caused by drying for a period of 210 days after the fabrication of specimens has been investigated. Experimental results have shown that micro silica and zeolite pozzolans improve the microstructure of the evaluated concrete, which improves the mechanical properties. In fact, the replacement of cement with pozzolans has made the parts of the transition zone of the specimens better and condensed. Shrinkage test results also show that zeolite and micro silica pozzolans lead to a significant reduction in drying shrinkage. Drying shrinkage of the concrete containing 15% zeolite and 7.5% micro silica decreased by 32% and 15% compared to the control concrete containing expansive materials at the age of 210 days, respectively.