Effect of Magnesia and Polypropylene Fibers on Mechanical Properties in Particular Fire Resistance of Self-Compacting Concrete

Selfcompacting concrete (SCC) is a type of concrete with high plasticity and strength against segregation. It does not need vibration because it is able to flow under its own weight, completely filling the formwork and achieving full compaction. In this paper, efforts have been made to present a certain design mixture for making SCC including microsilis, and also to improve its physical and mechanical properties against fire by adding polypropylene fibers (PPF) and magnesia. The effect of two different amounts of PPF and four different amountsof magnesia on compressive strength, tensile strength and modulus of elasticity at the ages of 7, 11, 28, 42 and 90 days is studied. 15 primary design mixtures with variation in aggregates, filler and super plasticizer have been made, and experimental tests consisting of slump, J loop, U box, L box and V hooper have been conducted. A suitable design mixture has been chosen on the basis of compressive strength for further laboratory tests. 150 cubic and 34 cylindrical samples have been prepared and tested for evaluating compressive strength, tensile strength and modulus of elasticity. Results indicate that polypropylene fibers can increase tensile strength and fire resistance, and magnesia with 100 μm segregation can increase compressive strength of SCC.