Performance of metakaolin and Portland cements in ettringite formation as determined by ASTM C 452-68: kinetic and morphological differences

In this study, the results of prior XRD and Le Chatelier-Ansttet test experiments were re-verified in terms of a relative parameter, the Length Growth Rate, Vcl(=ΔL (%)/day). For this purpose ASTM C 452-68 testing was conducted for 2 years on 40 cements, 10 Portland cements-6 OPCs and 4 SRPCs-and 30 blended cements containing 20%, 30% and 40% metakaolin (M pozzolan). ASTM C 452-68 specimens were manufactured with all cements and their daily length growth rate was calculated by dividing the measured increase in length, ΔL (%), by the number of days lapsing since the preceding measurement. Additional experiments were also run: chemical analysis, XRD and SEM analysis of ettringites and tests to determine specific properties of some cements tested. The results have once again borne out that: