Influence of Distribution Modulus on the Compressive Strength of Ultra‐High‐Performance Concrete with Coarse Aggregate (UHPC‐CA)

The Modified Andreasen and Andersen model (MAA model) is commonly chosen to realize condensed particle packing in ultra‐high‐performance concretes (UHPCs). In the MAA model, the q (distribution modulus) is a parameter that plays a critical role in the UHPC matrix design. The objective of this study is to figure out the influence of the q for the compressive strength of UHPC‐containing coarse aggregate (UHPC‐CA). Therefore, a series of investigations were conducted, covering the following aspects: first, the traditional design procedure, based on the MAA model, of UHPC‐CA is revised by taking water and steel fibers into account in the particle packing system. The results show that the revised design process of UHPC‐CA yielded more excellent products with better workability and compressive strength. Second, different q values which are 0.2, 0.21, 0.22, 0.23, and 0.25 are employed. The results show that when q is 0.25, the maximum compressive strength can be achieved. However, the flowability decreases with the increase of the q value. Third, an empirical calculation of the optimal coarse aggregate content in the light of different q values and maximum size of coarse aggregate are proposed.