Effect of Steel Fibers on Properties of Modified Reactive Powder Concrete

Farah Saeed Rasheed,Khalil Ibrahim Aziz

doi:10.11648/j.engmath.20210501.11

Abstract

This paper provides the result of an investigation to use of crushed brick as aggregates which was collected from the demolition waste of buildings from different sites then crushed with (maximum size 10 mm) in producing modified reactive concrete MRPC, which was presented by replacement the cementation binder (cement +silica fume) of original reactive powder concrete by 25% of crushed brick aggregates. The objective of this work is to study the effect of different type of steel fibers added in ratio 1% on the flowability and mechanical properties of reactive powder concrete and modified reactive powder concrete, which was micro steel fiber and hooked end steel fiber. The mechanical properties are examined by the tests of compressive strength, split tensile strength and flexural strength. The results showed that the compressive strength at 28 days of ORPC was 126.46 MPa, 120 MPa for the two types of steel fibers micro, hooked respectively. For the mix MRPC with micro, hooked the compressive strength at 28 days decreased by 1.53% and 1.15%, compared with those of the RPC made with micro, hooked steel fibers. And observed from the experimental results that two mixtures (RPC and MRPC) with micro steel fiber gave higher mechanical properties compared with the hook end.

Highlights

Reactive Powder Concrete (RPC) is a special type of ultrahigh-performance concrete (UHPC), with high ductility and advanced mechanical properties
There is a slight decrease in compressive strength for modified reactive powder concrete (MRPC) about 1.5% and 1% with those of the RPC made with micro and hooked steel fibers respectively
It is clear that the highest compressive strength recorded for the RPC and MRPC, which contain micro steel fiber than hooked end, and the lowest value of compressive strength was showed with mixes content hooked end steel fibers

Summary

Introduction

Reactive Powder Concrete (RPC) is a special type of ultrahigh-performance concrete (UHPC), with high ductility and advanced mechanical properties. The term Reactive Powder Concrete has been utilized to describe a fiber-reinforced, superplasticizer, silica fume-cement mix with exceptionally water-cement ratio (w/c) and presence of very fine quartz sand with size (0.15-0.40mm) rather than the coarse aggregate. Because of the utilization of exceptionally fine sand rather than ordinary coarse aggregate, the cement content in the RPC is as high as 800 to1000 kg/m3, silica fume (SF) content is regularly over 25% by the weight of cement. The high content of cement and SF can raise the hydration heat and which may be caused by shrinkage issues To conquer these issues, some mineral admixtures were utilized to supplant concrete or decrease the SF amount [3]. In order to enhance the fracture properties and improved tensile cracking, decreased crack width ductility, and post-cracking toughness, and spacing fibers are incorporated in RPC even when the amount of added fiber is low [5,6,7]

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Conclusion