A mix constituent proportioning method for concrete containing ternary combinations of cements

This article reports a laboratory experimental programme that investigated the performance of concrete made with ternary combinations of Portland cement (PC) with pulverised fuel ash (PEA), granulated blastfurnace slag (GBS) and silica fume (SF), with the aim of developing a simple concrete mix constituent proportioning method. The test mixes used combinations of these cements that conformed to ENV 197-1. All mixes used gravel aggregated mixes and a superplasticiser to achieve slump class S2 (60–90 mm) to provide characteristic cube strengths from 20 to 60 N/mm2. Standard cube strengths were measured up to 180 days. Recommendations are made for the optimum PC replacement level to achieve the highest cube strength at 28 and 180 days for mixes both with and without silica fume. The data have been generalised and fitted to the familiar format of the BRE Design of Normal Mixes to allow the proportioning of the concrete mix constituents. A visual from of the mix design method has been adopted such that the combinations of cements that can be used to achieve particular characteristic cube strengths are simple to identify.