Effect of Slag on the Porosity and Microstructure of HPC Reinforced with Hybrid Steel Fiber

Abstract

Due to their structural and economic performance, high performance metal fiber concretes are increasingly used in construction, but with the addition of metal fibers, workability decreases as the amount of fibers added increases. In order to improve workability, a larger quantity of fines should be used than for ordinary concrete. The use of granulated slag reduces the amount of clinker needed to make cement. It is considered that granulated slag improves the workability of concrete. According to Manai, this is due to the very low rates of water adsorption by the granulated slag grains at the start of mixing. Also, the addition of granulated slag has a positive effect on the porosity, but also on the microstructure of the hydrates. These two characteristics are factors determining the compressive strength and durability of the cement paste. The aim of this study is to define the effect of blast furnace slag on the porosity and microstructure of high performance fibre-reinforced concrete. The results of SEM and DRX observation of the microstructure of the concrete samples show that the addition of ultra-fine granulated slag resulted in a relative improvement in porosity and microstructure.