Supplementary Cementitious Materials (SCMs) in Cement Mortar
In this chapter, the performance of the blended cement mortar with carbonated solid wastes, including physico-chemical properties, morphology, mineralogy, compressive strength, and autoclave soundness, is illustrated. The specification of performance test
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Supplementary Cementitious Materials (SCMs) in Cement Mortar
Abstract In this chapter, the performance of the blended cement mortar with carbonated solid wastes, including physico-chemical properties, morphology, mineralogy, compressive strength, and autoclave soundness, is illustrated. The specification of performance testing for constriction materials with carbonated solid waste is also provided. In general, a high carbonation conversion of solid waste exhibits a higher mechanical strength in the early stage than pure Portland cement mortar. Moreover, the mortar with carbonated solid waste generally possesses superior soundness to the mortar using fresh solid waste. Since the chemistry of the cement hydrations is complicated and has not been completely clear, the principles and mechanisms of performance enhancement due to the use of carbonated waste in blended cement system are reviewed and discussed.
15.1
Introduction
Cement is a binder substance used in construction that sets and hardens to bind other materials together. The most widely used cement is for producing mortar in masonry and concrete (a combination of cements and aggregates to form a strong building material). Fresh alkaline solid wastes, such as iron and steel slags [1], fly ash [2], and bottom ash [3], have been extensively evaluated for potential use as supplementary cementitious materials (SCMs) in a blended cement and/or concrete block. According to a report from the Portland Cement Association [4], the use of SCMs in blended cement could increase the later-age strength of the concrete, as compared with the use of only Portland cement. SCMs can be divided into two categories: (1) self-cementing or (2) pozzolanic. Self-cementing materials react in a similar manner to Portland cement. In contrast, the pozzolanic materials (primarily siliceous in composition) does not exhibit cementitious properties in the presence of water [5]. In those alkaline solid wastes, several components are known to contribute the hydration of cement, thereby enhancing the strength development of cement. For example, b-C2S and C3S are known as the primary strengthcontributing hydraulic phases in Portland cement (see details in Sect. 15.3: Cement Chemistry). However, in some case, it also may reduce the early-age strength of the © Springer Nature Singapore Pte Ltd. 2017 P.-C. Chiang and S.-Y. Pan, Carbon Dioxide Mineralization and Utilization, DOI 10.1007/978-981-10-3268-4_15
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Supplementary Cementitious Materials (SCMs) in Cement Mortar
concrete and cement. As a result, in this section, the challenges in the utilization of fresh solid wastes as SCMs are addressed. To overcome the barriers, an alternative is proposed and illustrated by utilizing the carbonated solid wastes (from accelerated carbonation) as SCMs.
15.1.1 Utilization of Fresh Solid Wastes as SCMs Table 15.1 presents the uses of fresh alkaline solid wastes as SCMs in cement and/or concrete. For instance, basic oxygen furnace slag (BOFS) and fly ash (FA) are accepted as a pozzolanic martial a
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