Metakaolin as an Active Pozzolan for Cement That Improves Its Properties and Reduces Its Pollution Hazard

摘要: Prepared metakaolin produced by calcination of a kaolin sample at 750°C after soaking for 5 hrs was tested as an active pozzolan locally cement. Blended pastes partially replaced ordinary Portland cement with different amounts 5%, 10% and 15% were prepared, then they hydrated water various time intervals 1, 3, 7, 14 28 days. At each interval, the paste specimens compressive strength, hydration kinetics followed up using differential scanning calorimetry, X-ray diffractometry analyses electron microscopy techniques. Results showed that blended OPC-MK10 recorded highest strength values all times reaching 33.10, 86.40, 101.20, 112, 122 MPa increasing age compared neat samples which 31.70, 65.20, 72.6, 82 101.30 respectively. Meanwhile, blend decrease in free CaO content 4.07%, 4.27%, 4.23%, 4.19%, 4.11% 5.15%, 5.42%, 5.61%, 5.96% The DSC thermograms results hardened OPC-Mk10 days formation materials mainly calcium silicate hydrates, sulphoaluminate hydrates aluminates hydrates. both OPC- MK10 that, intensity hydroxide peaks lower than case OPC, while peak products higher OPC. Scanning micrographs indicated denser micro- structure to OPC hydration.