Limestone-calcined clay-silica fume blended cement: Statistical modelling and multi-attribute optimization through Derringer’s desirability function

Abstract

The Utilization of supplementary cementitious materials (SCMs) as clinker replacement, is the most effective way to reduce CO 2 emissions in the rapidly growing cement industry. The present paper investigates the synergistic effect of Hydroxy propyl methyl cellulose (HPMC) - Polycarboxylate ether (SP) based superplasticizer on limestone-calcined clay-silica fume blended cement (LC 3 ) through the Box-Behnken design (BBD) of response surface methodology (RSM). For this comprehensive study, LC 3 -50 blend consisting of 50 % OPC clinker, 30 % Calcined Clay, 15 % Limestone and 5 % Gypsum was prepared. In order to achieve improved strength LC 3 -50 blend; silica fume (SF) was replaced at different percentages level i.e., 0 %, 3 %, and 6 % by wt. of clinker powder. Statistical optimization was done, altogether 27 design mixes were cast and tested. BBD was employed to investigate the effects of four input parameters i.e., Silica fume (SF) (0–6 %), HPMC (0–1 %), SP (0–1 %) and flow value (120 – 160 mm) to all the dependent responses i.e., Water Binder ratio, Compressive strength (7 and 28 days) and Modulus of Rupture (MOR). Apart from these properties; Scanning Electron Microscope (SEM) was used to study the microstructural changes. The results provide insight into the interaction of SF and SP along with the role of HPMC in cementitious system.