EFFECT OF IRON POWDER PARTIALLY USED AS PORTLAND CEMENT REPLACEMENT ON THE STRUCTURAL PROPERTIES OF CONCRETE

Abstract

Concrete is the most usable material in the construction industry, as a porous material, it is suggested to many chemical attacks. It required to improve its quality during the time using nanoparticles. Nanotechnology offers the possibility of great advances of concrete in construction and can reduce its porosity. The nanotechnology improves the materials bulk properties, controls nanoscale attack on Alkali Silicate Reaction (ASR) and lowers level of environmental attack. Therefore, the use of nanoparticles in the concrete has many benefits. In this research, the iron oxide particles were used in the concrete to investigate the physical and mechanical properties of concrete. The concrete was made using a grade M25 for the mix design and the water-cement ratio was considered varied from 0.500 to 0.526. In this study, the effect of iron powder (Fe2O3) partially used as cement replacement on the physical and mechanical properties of concrete exposed to chemical attacks was experimentally investigated. For this purpose, Portland cement was partially replaced by 1.5, 2.5, 3.5, and 5% by weighing of iron powder. The workability of the fresh composite concrete was determined using cone Abrams method, mechanical properties were determined included compressive and tensile strengths at 7, 14, and 28 days and durability evaluated by water absorption, permeable porosity, sorptivity, chemical attacks, and chloride penetration. The durability was evaluated by exposing the specimen to sodium chloride and hydrochloric acid for a period of 28, 45 and 60 days. The structural performance was investigated and compared to the traditional concrete with the concrete containing iron powder. VI | P a g e The results showed that the compressive and tensile strengths improved with a certain level of iron powder. However, the maximum value was gained at 2.5 % cement replacement by weight for compressive strength and 1.5% for tensile strength. The workability of the fresh mixtures decreased when iron powder amount increased. It was observed that the porosity decreased respectively by 21.88 and 26.77% at 1.5 and 2.5% replacement. In terms of durability performance, the results showed that the addition of iron powder lessen the diffusion of chloride ion within the concrete and prevent it from reaching the steel reinforcement. The specimen of all the different mixtures showed more degradation when exposed to 3% hydrochloric acid solution for 28, 45 and 60 days than the one exposed to 2% hydrochloric acid solution. From result obtained, when 2.5% of iron powder replaced by Portland cement, the flexural strength increased by 18.22% at 28 days for the case of the non-reinforced concrete beam (NRC-B). The reinforced concrete beam (RC-B) with 2.5% of iron powder was judged to be structurally more efficient than the control specimen. Moreover, this present study shows that it is important and benefits to improve concrete properties by using micro-particles materials as a partial replacement of Portland cement.