Abstract

Reactive Powder Concrete RPC is comprise of (cement, quartz powder, sand, and superplasticizer) mixture with low water/cement ratio. It has not coarse aggregates and characterized by highly dense matrix, high strength concrete, excellent durability, and economic. This study aims to investigate fresh and hardened properties of locally cast RPC with several available economical materials such as silica fume (SF), fly ash (FA), steel fiber (STF), and glass fiber (GF). Experimental investigation were performed to study the effectiveness of partial replacement of cement by SF or FA to reach ultra-high strength concrete, effect of additional materials STF or GF in order to improve the fracture properties of the RPC mixes, and influence of the treated with normal water as well as with hot water. Fifteen different RPC mixes were cast with 20, 25, 30, and 35% cement replacement by SF, 25% cement replacement by FA, and another proportions taken combination between SF and FA with percentages 15, 20, 25% FA and constant 10% SF. Varying fiber types (steel fiber or glass fiber) added to concrete by different percentages 1, 2, and 3%. Specimens were treated with normal water 25ᵒC and hot water at 60ᵒC and 90ᵒC by 2 mixes with silica fume content 25% of binder and steel fiber content 2% by total volume. Performance of the various mixes is tested by the slump flow, compressive strength, flexure strength, splitting tensile strength, and density. The production of RPC using local materials is successfully get compressive strength of 121 MPa at the age of 28 days at standard conditions and normal water curing 25°C with Silica fume content 25% of binder and steel fiber content 2% by total volume of RPC and water/binder ratio of 0.25. The results also showed the effect of curing by hot water 60 and 90°C, it is observed that compressive strength increases proportionally with curing temperatures and a compressive strength of 149.1 MPa at 90°C for 1days was obtained.

Highlights

  • Concrete is a very used construction material and has undergone many researches and development over the last decade

  • The compressive strength of reactive powder concrete (RPC) mixes at various replacement of cement by (SF or fly ash (FA), and combination between them) at 7, 14, and 28 days age are presented in table VII and Fig. 1

  • 1- When the silica fume (SF), and FA content increases, the flow ability of RPC decreases, as the increase of soft materials in the mix leads to increased density of the mixture

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Summary

Introduction

Concrete is a very used construction material and has undergone many researches and development over the last decade. Reactive Powder Concrete-RPC is a comparatively new cementitous material. Coarse aggregate used in normal concrete is completely replaced by fine quartz sand and crushed quartz. High Performance Concrete (HPC) may provide an ultimate compressive strength of 50 to 100 MPa [1], but RPC is characterized very high performance in mechanical properties, in compressive strength, which can be in the range of 150 to 800 MPa. RPC was discovered by the scientific division of Bouygues in the early of 1990s, it is a new generation cement based composite developed by microstructural enhancement techniques. The RPC configuration is free of empty aggregates and is different from normal concrete. Fine powders used such as quartz sand and crushed quartz, with sizes ranging from 45: 600 micrometers. Many successful applications of RPC such as the 60 m span Sherbrook Bridge in Canada; the 25-meter span Future Bridge in USA, used for sea walls anchors in Portugal, used for vehicular bridges in Australia, and has been used in the production of structural beam components, manhole covers, road accessories and others

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