The influence of granite powder waste and the addition of fly ash on concrete bleeding

Abstract

Bleeding is a common problem in concrete slabs, and may lead to serious damage. The goal of this article is to understand the impact of alternative binders and their properties on the bleeding of concrete. Therefore, the impact of the type of binder on the bleeding process is investigated. The results show that the addition of granite powder or fly ash allows for the increased control of the bleeding process. It was found that a finer particle size distribution (PSD), an increased specific surface area (SSA), and a higher bulk density may reduce the amount of dispensed water in the concrete mix. Furthermore, the use of additives with an increased SSA leads to even a 30% reduction of the bleeding rate of mixes. The utilization of additives with a finer PSD than cement enables a 37% reduction of the bleeding rate of mixes. The influence of bleeding on compressive strength was assessed using destructive and non-destructive tests: Replacing 30% of cement with granite powder leads to a 30% reduction of concrete strength after 28 days of curing; on the other hand, replacing 30% of cement with siliceous fly ash leads to an 18% reduction of strength. Importantly, bleeding was also found to lead to the heterogeneity of the physical and mechanical properties across the concrete section. Consequently, the proper control of the bleeding process leads to more homogeneous properties of concrete across its cross-section.

Decision-making model using the Analytical Hierarchy Process for the selection of the type of concrete and the method of its maintenance in dry, hot climate conditions

“…Practical measures to mitigate these effects include actions such as: changes in the formulation of the concrete mix (e.g., the use of metallurgical cement or a lower cement content [7]), modifications to the structure design (such as additional reinforcement, prestressing, expansion joints) or component cooling mixes or installation of cooling pipes or replacement of part of the mixing water with crushed ice [8]. In construction practice, there are also many other methods of modifying the properties of concrete [9,10], but new low-cost curing methods are still being sought.…”