Mitigation of Additional Overdesign in Portland Cement Concrete by Optimizing the Cementitious Materials Content

Abstract

More cement does not necessarily make better concrete or expedite construction schedules. In contrast, concrete with lower cementitious content can reach sufficient strength on time to avoid construction delays and last longer. Standard specifications require concrete overdesign (OD) for decades, but studies assessing the actual OD magnitudes are rare. This experimental study aimed to identify the required cementitious materials content (RCC) to meet the OD based on 958 compressive strength tests (σ) representing 8200 m3 of ready-mixed concrete for threshold buildings. The actual OD in commercial concrete appears to be 7 to 21% higher than required. The cementitious materials content should be reduced between 6 and 17% so that concrete can reach the required compressive strength (f’cr) without cement overconsumption. The additional overdesign (AOD) increased significantly as the specified compressive strength (f’c) increased, indicating that concrete producers can be more cautious when the f’cr is higher. Further research is needed to expand the range of cementitious contents and applications.