Supplementary Cementitious Materials for Concrete: Characterization Needs

Abstract

A wide variety of materials are currently used as supplementary cementitious materials (SCMs) for concrete, including natural materials and byproducts from various industries. Historically, natural SCMs, mostly derived from volcanic deposits, were common in concrete. In recent years, the dominant SCMs have been industrial by-products such as fly ash, ground granulated blast furnace slag (GGBFS), and silica fume. There is currently a resurgence of research into historic and natural SCMs, as well as other alternative SCMs for many reasons. The primary benefits of SCM use in improvement of long-term mechanical performance, durability, and sustainability are widely accepted, so local demand for these materials can exceed supply. This paper describes some of the SCMs that are attracting attention in the global research community and the properties and characteristics of these materials that affect their performance. Special attention is paid to the importance and demands of material characterization. Many SCMs do not necessarily lend themselves to characterization methods used in standardized test methods, which sometimes fail to describe the properties that are most important in predicting reactivity.

Determination of particle size, surface area, and shape of supplementary cementitious materials by different techniques

“…The use of SCMs in concrete production is desirable both for emission reduction and energy conservation as well as for the improvement of concrete mechanical and durability properties [2]. SCMs are mostly by-products of industrial processes [3] and in most cases the quality of these materials is less controlled during their production than in the direct production of a primary product from a purpose-designed process, resulting in materials with varied characteristics [4].…”

Assessing, Understanding and Unlocking Supplementary Cementitious Materials

“…Identifying the parameters that control SCM reactivity in blended cements is not trivial due to the often complex interplay of reactions. The purely empirical testing approach focusing on macroscopic performance has delivered a quite fragmented chemical understanding of SCM reactivity, even for widely used blastfurnace cements [14]. Analytical, more fundamental approaches have made considerable progress as of lately, as for instance demonstrated by the succesfull application of equilibrium thermodynamics in predicting hydrate assemblages of various blended Portland cements [15].…”

Introduction of a mineral powder as a type of natural cementitious material in concrete: An experimental program

“…Recently, SCMs, have received increasing attention for the role that they play in bringing down the carbon footprint of concrete, since the energy use and CO 2 emissions from PC clinker manufacturing significantly outweigh those of other concrete components, and SCMs have a smaller environmental impact than PC clinker …”

“…Natural pozzolanic materials, which mostly need only are conditioning of particle characteristics by sieving and grinding . Further, measuring the specific surface area and particle size distributions for these materials are important and developing and refining accurate tools are an essential part of material characterization …”