Influence of expansive cement on rheological, strength performance and morphological characteristics of self-compacting concrete

This research is focused on the influence of type K expansive cement (calcium sulfoaluminate-belite cement) blended with self-compacting concrete (SCC) in the presence of alccofine and silica fume. The present work intends to evaluate the synergistic effect of expansive cement in various proportions from 0 to 15 % by cement weight by examining the rheological properties, mechanical strength and expansive characteristics for M30, M40 and M50 grades of SCC. Results revealed that the incorporation of expansive cement is constructive in improving fresh state properties, mechanical performance and reducing shrinkage properties effectively due to the for-mation of additional ettringite and calcium hydroxide. Results of fresh properties of expansive SCC show a good agreement with European standards. The test results illustrate a positive influence on strength properties of SCC at the early age with the inclusion of 10 % of expansive cement due to the formation of additional ettringite and calcium hydroxide. Incorporating 10 % of expansive cement enhanced the compressive strength by 12 %, 9% and 7 % for M30.M40 and M50 grades of SCC respectively relative to reference SCC at 28 days. However, a slight strength reduction in compressive strength is noticed for SCC with the inclusion of higher percentage (15 %) of expansive cement. The effect of expansive cement on the morphological characteristics of SCC was assessed by employing SEM, EDS, XRD and FTIR techniques to validate the experimental results. On the other hand, addition of expansive cement and supplementary cementitious materials in the production of SCC minimizes the use of Portland cement and significantly reduces carbon footprint.