Production of Ultra-High-Performance Concrete with Low Energy Consumption and Carbon Footprint Using Supplementary Cementitious Materials Instead of Silica Fume: A Review

Mays A Hamad,Mohammed Nasr,Zainab Al Masoodi,Rafid Alkhaddar,Zainab Al-Khafaji,Khalid Hashim,Patryk Kot,Ali Shubbar,Osamah Al-Hashimi

doi:10.3390/en14248291

Abstract

The increase in cement production as a result of growing demand in the construction sector means an increase in energy consumption and CO2 emissions. These emissions are estimated at 7% of the global production of CO2. Ultra-high-performance concrete (UHPC) has excellent mechanical and durability characteristics. Nevertheless, it is costly and affects the environment due to its high amount of cement, which may reach 800–1000 kg/m3. In order to reduce the cement content, silica fume (SF) was utilized as a partial alternative to cement in the production of UHPC. Nevertheless, SF is very expensive. Therefore, the researchers investigated the use of supplementary cementitious materials cheaper than SF. Very limited review investigates addressed the impact of such materials on different properties of UHPC in comparison to that of SF. Thus, this study aims to summarize the effectiveness of using some common supplementary cementitious materials, including fly ashes (FA), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ashes (RHA) in the manufacturing of UHPC, and comparing the performance of each material with that of SF. The comparison among these substances was also discussed. It has been found that RHA is considered a successful alternative to SF to produce UHPC with similar or even higher properties than SF. Moreover, FA, GGBS and MK can be utilized in combination with SF (as a partial substitute of SF) as a result of having less pozzolanic activity than SF.

Highlights

The results indicated that the highest compressive strength and flexural strength were achieved for the ground granulated blast furnace slag (GGBS), with specific surface areas of 556 m2 /kg at both percentages of replacement
This paper reviewed the investigates that utilized SCMs other than silica fume (SF) in the manufacturing of Ultra-high performance concrete (UHPC) and comparing their performance in comparison to that of SF
There are few studies that have dealt with carbon dioxide emissions and the energy consumed for SCMs in the manufacture of UHPC, taking into account materials manufacturing processes, the resulted compressive strength, the curing used and other details of concrete

Summary

Introduction

Ultra-high performance concrete (UHPC) or identified as reactive powder concrete (RPC) point to a new category of materials based on cement that exhibited exceptional mechanical and durability characteristics [1,2,3,4,5]. The typical mixture of UHPC comprises cement, supplementary cementitious materials (SCMs, including fly ashes, metakaolin, silica fume, etc.), sand (fine sand), glass or quartz powder, high-range water-reducing admixture (HRWR), low water content and steel fibers [14,15,16,17]. Coarse aggregate is eliminated in most UHPC mixtures [14,18,19,20] to increase the homogeneity, overcome the weakness at the interfacial transition area between the coarse aggregate and paste matrix, as well as remove the stress concentration at the contact points between the coarse aggregate particles [21,22,23]

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