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目的研究高强混凝土的早期收缩性能,探讨饱水陶粒对混凝土早期收缩的影响,修正参数得到适宜高强混凝土收缩的数学模型,并对复合骨料高强混凝土收缩模型进行定义.方法采用非接触式试验,将混凝土成型面暴露于室内空气中,带模测试了混凝土的早期收缩.结果高强混凝土的收缩主要发生在14 h之内.14 h收缩值是3 d收缩值的92%,3 d收缩值为3 060μm.m-1;饱和吸水陶粒可改善高强混凝土早期收缩性能,陶粒的最佳体积替代量为41%,14 h、72 h收缩值降幅分别可达48%和43%.随着陶粒的增加,混凝土强度逐渐降低.结论采用饱水陶粒替代混凝土中粗骨料,发挥其内养护作用,可以达到降低高强混凝土早期收缩的目的.修改后的超高强复合骨料混凝土收缩模型与试验结果吻合较好.
Objective To study the early shrinkage of high-strength concrete, to study the influence of saturated water ceramsite on the early shrinkage of concrete, to get the suitable model for the shrinkage of high-strength concrete, and to define the shrinkage model of high-strength concrete.Methods Non-contact test , The concrete forming surface was exposed to the indoor air and the mold was tested for the early shrinkage of the concrete.Results The shrinkage of high strength concrete occurred mainly within 14 h.The shrinkage value at 14 h was 92% (3 060μm.m-1). Saturated water-absorbing ceramsite could improve the early shrinkage of high-strength concrete. The best replacement volume of ceramsite was 41%, and the shrinkage value of 14 h and 72 h decreased by 48% and 43%, respectively With the increase of ceramsite, the strength of concrete gradually decreased.Conclusion The purpose of reducing the early shrinkage of high-strength concrete can be achieved by replacing the coarse aggregates with saturated water ceramsite and exerting the inner curing effect.The modified ultra-high strength composite aggregate concrete shrinks The model is in good agreement with the experimental results.