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设计制作5种HCSA膨胀剂掺量的高强自密实混凝土试块,通过混凝土工作性、抗压强度和自由膨胀率以及在钢管约束条件下混凝土自应力值测试,研究HCSA膨胀剂掺量对高强自密实混凝土性能的影响.结果表明:掺入膨胀剂对混凝土工作性影响较小;随膨胀剂掺量增加,混凝土自由膨胀率逐渐增大,而28d抗压强度则快速下降;膨胀剂水化主要集中在混凝土硬化早龄期,自由膨胀变形于12~15d范围内达到稳定.在钢管约束条件下,混凝土膨胀稳定滞后,且当膨胀剂掺量为8%~12%,混凝土膨胀稳定时自应力值达3.2~3.7 MPa.最后,基于试验与理论分析结果,建立钢管约束条件下混凝土限制膨胀模型及自应力值计算公式,计算结果与试验结果吻合较好,可供工程设计参考.
Design and manufacture of high strength self-compacting concrete blocks with five kinds of HCSA expansive admixtures. Through the test of concrete workability, compressive strength and free expansion, and self-stress of concrete under steel confinement conditions, The results show that: the dilatancy agent has little effect on the workability of concrete; with the increase of dilatant content, the free expansion rate of concrete increases gradually, while the compressive strength of 28 d decreases rapidly; Concentrated in the early age of concrete hardening, the free expansion deformation reaches a stable range of 12 ~ 15d.When the steel pipe constraints, the expansion of concrete stability and delay, and when the expansion agent content of 8% to 12%, the stability of self-stress expansion of concrete Finally, based on the experimental and theoretical analysis results, the formula for calculating the limited expansion model and the self-stress formula for concrete under the constraint of steel tube was established. The calculation results agree well with the experimental results and are available for engineering design reference.