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Title: A thermodynamic model for C-(N-)A-S-H gel: CNASH{sub s}s. Derivation and validation

The main reaction product in Ca-rich alkali-activated cements and hybrid Portland cement (PC)-based materials is a calcium (alkali) aluminosilicate hydrate (C-(N-)A-S-H) gel. Thermodynamic models without explicit definitions of structurally-incorporated Al species have been used in numerous past studies to describe this gel, but offer limited ability to simulate the chemistry of blended PC materials and alkali-activated cements. Here, a thermodynamic model for C-(N-)A-S-H gel is derived and parameterised to describe solubility data for the CaO–(Na{sub 2}O,Al{sub 2}O{sub 3})–SiO{sub 2}–H{sub 2}O systems and alkali-activated slag (AAS) cements, and chemical composition data for C-A-S-H gels. Simulated C-(N-)A-S-H gel densities and molar volumes are consistent with the corresponding values reported for AAS cements, meaning that the model can be used to describe chemical shrinkage in these materials. Therefore, this model can provide insight into the chemistry of AAS cements at advanced ages, which is important for understanding the long-term durability of these materials.
Authors:
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Publication Date:
OSTI Identifier:
22395932
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 66; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; ALUMINIUM OXIDES; CALCIUM OXIDES; CALCIUM SILICATES; CHEMICAL COMPOSITION; DENSITY; GELS; HARDNESS; HYBRIDIZATION; HYDRATES; PORTLAND CEMENT; SHRINKAGE; SILICA; SILICON OXIDES; SIMULATION; SLAGS; SODIUM OXIDES; THERMODYNAMIC MODEL; VALIDATION; WEAR RESISTANCE