Assessment of long-term reactivity of initially lowly-reactive solid wastes as Supplementary Cementitious Materials (SCMs)

Abstract

Recently, due to various reasons, the amount of commercial supplementary cementitious materials (SCMs) available for the concrete industry has depleted and hence a wide range of moderately to lowly active solid wastes are being considered as SCMs. However, using such wastes as SCMs needs an efficient and practical procedure to estimate their long-term reactivity. For this purpose, different mechanical and chemical testing schemes have been specified (e.g. Chapelle test, relative strengths, activity index, modified lime reactivity test, R3 method) to assess their reactivities. In this study, a wide range of solid wastes including incinerated bottom ash (IBA), different colored soda-lime glass powders, fluorescent lamp glass powder (FLGP) and pulverized fly ash (PFA) were tested to evaluate their reactivities. It was found that there were moderate correlations between 180-day relative strengths (RS180day) of standard mortars and the bound water content or portlandite consumption of the R3 method. Moreover, the mortar strength values of the modified lime reactivity test were adequately correlated with RS180day of the standard mortars. In comparison, the portlandite consumption values of the Chapelle test had a poor correlation with RS180day. In addition, the studied materials can be classified as lowly-reactive (IBA), moderately-reactive (MGP, BGP, WGP, GGP, BGP, FLGP) and highly-reactive (PFA) SCMs.