Rich reserves of limestone powder can be used as raw material for concrete,which is widely used in engineering practice.In order to study the influence of limestone powder on the early hydration of cement,five kinds of limestone powder are selected as additive of cement mortar briquette.In addition,another six groups of samples were made without limestone in the same conditions.The research shows that the compressive strength and flexural strength of cement mortar briquette at 7 d and 28 d is carried out.Study shows that the activity index of limestone powder which has stayed for 7 d is more t...