分段推定混凝土抗压强度方法探讨

Discussion on Estimating the Compressive Strength of Concrete by Subsection Deduction

为拓展JGJ/T 23—2011《回弹法检测混凝土抗压强度技术规程》和JGJ/T 294—2013《高强混凝土强度检测技术规程》的检测范围,使其具有更好的适用性,对回弹值与抗压强度关系散点呈分区段变化的特点进行了深入研究,采用分段测强曲线推定混凝土抗压强度的方法,制作了不同强度等级的足尺模型。在足尺模型中,试验制作了不同类型的结构构件,通过得到回弹值与抗压强度之间关系的散点图,对散点分布进行分析,发现散点分区段呈现不同的变化规律,之后将不同区段的散点分别进行回归拟合,得到一条连续的回归测强曲线,实现分区段推定混凝土抗压强度。结果表明:分段测强曲线推定混凝土强度拓展了测强曲线的适用范围,同时提高了测强曲线的精度,使JGJ/T 23—2011《回弹法检测混凝土抗压强度技术规程》和JGJ/T 294—2013《高强混凝土强度检测技术规程》具有更强的适用性,为日后混凝土抗压强度的检测提供更好的指导。

To expand the testing scope of JGJ/T 23—2011 Technical specification for inspecting of concrete compressive strength by rebound method and JGJ/T 294—2013 Technical specification for strength testing of high strength concrete,and to make them have better applicability,this paper studies the relationship between rebound value and compressive strength in detail and deduces the compressive strength of concrete by subsection strength curve.In the full-scale models,it makes many different types of structural members,and obtains the scatter plot of the relationship between rebound value and compressive strength,and analyzes the distribution of scatter points.It finds that the scattered points in different sections have different changing rules,and regresses the scattered points in different sections to get a continuous regression curve.The results show that the concrete strength inferred from the piecewise strength curve extends the applicable range of the strength curve,and also improves the accuracy of the curve,which makes JGJ/T 23—2011 Technical specification for inspecting of concrete compressive strength by rebound method and JGJ/T 294—2013 Technical specification for strength testing of high strength concrete more applicable,it provides a better guidance for the detection of compressive strength of concrete in the future.