Factors Affecting Slump Loss of Concrete-Admixtures
Nowadays, there are many kinds of admixtures and cement, and the compatibility between different admixtures and different kinds of cement is also very different. The compatibility of cement with additives is related to the amount of adsorbed additives. Additives are mainly adsorbed to the surface of hydration products. The faster the hydration and the larger the specific surface area of the hydration products produced, the more adsorbents the cement adsorbs and the worse the compatibility with the admixtures. Among the mineral compositions of cement clinker, C3A is the fastest hydration, and its hydration products have larger specific surface area, so it adsorbs more admixtures. The adsorptive capacity of several minerals in cement to additives is as follows:
C3A > C4AF > C3S > C2S
After cement mixing, the additives are adsorbed to the surface of cement particles. First, C3A and C4AF absorb water reducers and react rapidly with hydration. When C3S and C2S, which account for the majority of cement mineral composition, begin to adsorb and react with hydration, the concentration of additives in liquid phase has become very low, and the potential value on the surface of cement particles decreases, so the workability of concrete is poor. The slump retention decreases.
Shijiazhuang City Horizon Chemical Industry Co., Ltd. provide cement and concrete additive materials, like cement grinding additive Triisopropanolamine and Diethanolisopropanolamine, also the concrete water reducer-polycarboxylate superplasticizer to improve the cement quality and concrete slump retention, which can better meet the projects requirement.