大掺量石灰石粉对水泥胶砂性能的影响

Impact of High-volume Limestone Powder Admixture on Properties of Cemented Mortar

研究石灰石粉在20%、30%、40%和50%大掺量下的水泥胶砂性能。试验结果表明:石灰石粉可发挥微晶核效应,减少水泥净浆标准稠度用水量,缩短凝结时间,降低胶砂需水量比,具有一定的减水效应;石灰石粉可促进水泥早期水化放热,水泥胶砂的水化热和干缩率随石灰石粉的掺量增大而降低,故石灰石粉的掺入可降低混凝土开裂的风险;石灰石粉虽然在水化后期具有一定的活性,但大掺量的石灰石粉会使水泥胶砂后期强度损失较大,在实际应用中应当引起重视。

The paper made a study of the properties of cemented mortar with limestone powder admixture in proportion as 20%,30%,40% and 50%respectively.The test shows that the limestone powder can play a microcrystalline effect,reduce water consumption to achieve the standard water consistency of cement paste,shorten setting time,reduce water consumption ratio of cemented mortar and have certain water reduction effect.The limestone powder helps to promote cement early-stage hydration and heat release.Both hydration heat and shrinkage rate significantly reduce with increase of quantity of limestone power admixture.Therefore admixture of limestone powder can reduce the risk of concrete cracking.Although limestone powder has certain activity at late stage of hydration,large quantity of limestone powder admixture would cause significant loss of late-stage strength of the cemented mortar.So attention should be payed to practical use of limestone powder.