Chemical and physical approaches to improve the properties of concrete for application to nuclear related structures

Abstract

This paper evaluates three distinct approaches for their ability to improve material properties, extend the service life, and reduce environmental impacts of concrete. Specifically, the approaches are categorized as (i) chemical (use of supplementary cementitious materials (SCMs)), (ii) chemical and physical (use of limestone filler (LF)) and (iii) physical (use of steel fibres). Now more than ever, the construction industry is faced with designing structures and infrastructure including nuclear facilities, that are both durable, and sustainable. This study compares data reported in the literature on the effect of various SCMs (i.e. fly ash (SCM-I), ground granulated blast furnace slag (SCM-II), silica fume (SCM-III), and metakaolin (SCM-IV)), LF, and steel fibres on the compressive strength, porosity, and long term durability (sulfate attack, carbonation, alkali silica reaction and freeze–thaw resistance) of mortar and concrete. Key outcomes of this comparative study reveals that: (i) The incorporation of SCMs and LF can have beneficial effects on the properties and durability of mortars or concrete with the exception of carbonation resistance. (ii) Steel fibres can improve the mechanical properties and durability properties at dosages between 1% and 1.5% by volume of concrete. While the properties of steel fibre concrete are dependent on the physical feature of the steel fibres (such as type, shape and size), they are similar or greater than the properties of concrete without fibres. (iii) The advantages of steel fibre incorporation as a purely physical approach are comparable to a chemical approach of using SCMs (less than 30% replacement levels) as well as a combined chemical and physical approach which entrails the use of LF (less than 10% replacement).