Slag-fly ash based cementitious materials special for high performance concrete

Cementitious materials special for high performance concrete with high volume of fly ash and slag and less cement clinker were prepared by optimizing the proportion of ingredients and the size fraction and using an additive. The effects of grinding modes, gypsum amount and the mix proportion of slag to fly ash on the strength of the cementitious materials were studied. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) were used to observe the microstructure and hydration products and investigate the collaborative optimization effect between the activity and grading of the cementitious materials. The results show that cementitious materials have good mortar fluidity when the water-binder ratio (W/C) is 0.36, the compressive strength of colloidal mortar specimens cured for 28d is 58.9 MPa and the 28d flexural strength is 14.2 MPa, which have favorable properties of erosion resistance to sulfates. The concrete made from the cementitious materials has a better ability of carbonation resistance.