Durability and Theological characteristics of high-volume ground-granulated blast-furnace slag concrete containing CaCO_3/anhydrate-based alkali activator

摘要

In this paper, durability and rheological characteristics of binary blended mixtures incorporating high-volume ground-granulated blast-furnace slag (GGBFS) were assessed based on a series of laboratory tests. Various durability characteristics such as restrained shrinkage cracking, freeze-thaw resistance, carbonation resistance, and chloride ion diffusion resistance were comprehensively investigated. The experimental results verified that the high-volume GGBFS replacements with a CaCO3/anhydrate-based alkali activator effectively improved the overall durability performance, especially when a replacement level of 70% was used. The promoted durability was mainly attributed to the formation of dense microstructure and low capillary porosity resulting from the enhanced degree of latent hydraulic and pozzolanic reactivity of GGBFS in the presence of alkali activator, which transformed a number of weak phases in cement hydrates (Ca(OH)(2)) into dense calcium silicate hydrate (C-S-H) phases. It was also found that the flow behavior was largely affected by the GGBFS replacement level, use of alkali activator, and elapsed time after mixing. Based on the findings of the present study, the high-volume GGBFS replacement, up to 70-80 wt%, appears to be a substantial strategy for enhancing the durability and sustainability of concrete. (C) 2019 Elsevier Ltd. All rights reserved.