Volume-based design of ultra-low cement concrete

Built on volume-based concrete mix design (VCD) approach, the idea behind this study is to assess the sustainability and robustness of mortar mixtures subjected to variations in the two basic phases of paste and aggregate. The utilization of sand as cementitious paste volume (CPV) replacement can effectively lower cement consumption for improved sustainability. However, lowering CPV results in lower workability, especially when it falls below a certain limit. To address this issue, concurrent paste replacement and sand proportioning methods were proposed to push downwards the lower limit of CPV to allow minimal cement and maximal performance. An experimental program, consisting of three phases, was launched to investigate the effects of CPV and sand proportioning on sustainability, workability, and strengths. Optimal CPV and sand proportion for achieving the highest mortar performance at minimal cement content were identified, providing guidance for the design of ultra-low cement/carbon concrete (ULCC). Furthermore, elucidation on the ULCC mechanism was presented based on particle packing and film thickness theory.

Automated summary

Built on the VCD approach, this study aims to assess the sustainability and robustness of mortar mixtures by varying the paste and aggregate phases. The use of sand as a replacement for cementitious paste volume (CPV) effectively reduces cement consumption for improved sustainability. However, decreasing CPV leads to decreased workability, especially when it falls below a certain limit. To address this issue, concurrent paste replacement and sand proportioning methods were proposed for optimal mortar performance with minimal cement content. An experimental program was conducted to investigate the effects of CPV and sand proportioning on sustainability, workability, and strengths, and the optimal values were identified for the design of ULCC. Furthermore, the ULCC mechanism was explained based on particle packing and film thickness theory.