Performance of Compound Cementitious Materia! Compounded with Clinker and Limestone Powder and Coal Ash

摘要

Limestone powder and coal ash are selected to prepare compound cementitious material with clinker. It is found that with the increasing of mixture (including limestone powder and coal ash), the water amount for standard consistency of compound cementitious material increases and the flexural strength and compressive strength at 3 and 28 days decrease. Increasing of limestone powder can reduces the water amount for standard consistency. The compressive strength, flexural strength and cleavage strength decrease with the increasing of mixture. If the mixture dosage is 60%, when the ratio of limestone powder and coal ash is 8:2, the compressive strength is the highest. If the mixture dosage increases to 70%, when the ratio of limestone powder and coal ash is 7:3, the compressive strength is the highest. If the mixture dosage is 80%, the all strengths are very low. The compressive strength increases significantly with time, the compressive strength is greater than 50MPa at 90 days. Although the mortar strength of compound cementitious material is far below for mortar strength required by cement standard, but the middle-low strength grade concrete can be prepared by low water-binder ratio.