预拌泵送混凝土弧面对压法测强曲线及其应用

Research on the curve of strength measurement of ready mixed pumping concrete by arc pressure method and its application

为研究混凝土抗压强度与微小芯样径向对压强度关系,设计制作7个不同混凝土强度等级足尺结构模型,测试模型混凝土中直径38 mm微小芯样径向对压强度与直径100 mm标准芯样试件抗压强度,建立预拌泵送混凝土弧面对压法测强曲线,研究样本数量对回归测强方程误差与检测精度的影响,分析实际应用中存在的问题。结果表明:随样本数量增加,回归测强方程的统计误差减小;当样本数量为3个时的回归测强方程检测精度最高,样本数量为2个时的次之;建立的弧面对压法测强曲线具有稳健性和可靠性,可准确地预测预拌泵送混凝土结构实体强度;考虑工程检测的经济性,建议单构件检测时取样数量宜为3个,批量检测时对单个构件的取样数量宜为2个。研究结果可供结构混凝土强度质量检测与控制参考。

In order to investigate the correlation between compressive strength of concrete and radial arc compressive strength of micro core specimen,Seven full-scale structural models with different concrete strength grades are designed.The radial compressive strength of small core specimens with diameter of 38mm and the compressive strength of standard core samples with diameter of 100 mm in models concrete are measured,the strength curve of ready-mixed pumping concrete by arc pressure method is regressed.The influence of the number of samples on the statistical error and detection accuracy of the strength curve is studied,and the problems in practical application are analyzed.The results show that the average relative standard deviation of the strength curve decreases with the increase of the number of samples;when the number of samples is 3,the detection accuracy of the strength curve is the highest,followed by 2 samples;the strength curve of arc pressure method has robustness and reliability,and can accurately predict the actual strength of ready mixed pumping concrete structure;considering the economy of engineering testing cost,it is suggested that the sampling quantity for single component testing should be 3 pieces,and the sampling quantity for single component testing should be 2 pieces.The results can provide references for the quality inspection and control of structural concrete strength.