对比研究了减缩剂单掺及与减水剂复掺对混凝土早期收缩、水化热、开裂性能、抗压强度及劈拉强度的影响。试验结果表明，减缩剂内掺有效抑制了混凝土早期收缩，单掺和复掺下24 h减缩率分别达到了58％和50％；减缩剂延缓了水化热峰值的出现，降低了水化热峰值，使得水化反应平缓进行，有利于缓解温差收缩裂缝；减缩剂的掺入对混凝土的抗压和劈拉强度有不利影响，但明显提高了混凝土的抗裂性能；试验中也发现，复掺减缩剂和减水剂能降低单掺减缩剂对混凝土强度的不利影响，将这种不利影响控制在10％以内。%The effects of mixing with shrinkage reducing admixtures (SRA ) only and compounding with superplasticizer (SP) on early age shrinkage ,hydration heat ,cracking ,compressive strength and splitting tensile strength of concrete are comparatively investigated .The experimental results show that SRA can obviously reduce the early age (24 h) shrinkage of concrete . The addition of SRA results in a reduction in shrinkage of around 58% and 50% (compounding with SP ) at 24 h ,as compared to the control mixture .The appearance time of exothermic peak can be delayed ,and the peak value as well as the hydration heat of cement can be lowered by adding the SRA .The cement hydrate reaction with SRA is steady and SRA reduces the risk of temperature shrinkage cracking .The experimental results also show that SRA has a certain negative effect on the compressive strength and splitting tensile strength of concrete , and mixing with SRA reinforces the cracking resistance of concrete .It is also found that compounding with SRA and SP can reduce the negative effect within 10% .
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