Water Demand (or Specific Surface) of Aggregate as a Dominating Factor for SCC Composition Design

In the modern era of superplasticizer-based concrete technology, water demand (or specific surface) of aggregate is a significantly underestimated factor influencing cement paste demand in the self-compacting concrete (SCC) design process. The presented data show that it is the key factor for optimization criterion of SCC cement paste demand. Four models were taken into consideration (Bolomey, Stern, modified Loudon, and Relative Specific Surface), and all of them fit linearly very well (R2 ≥ 0.95) to the relative thickness of coating aggregate with cement paste (trel). This means that all of these models may be used interchangeably in the process of SCC design without any alteration (so there is no need to develop a new model). Including the water demand of aggregate in the design procedure in its proposed version sets the bottom limit of superplasticizer dose for laboratory trials, leaving only small gap for eventual minor adjustments.