西安建筑科技大学学报(自然科学版)

为研究高强钢筋与超高性能混凝土(UHPC)的黏结性能,考虑钢筋直径、锚固长度以及保护层厚度等因素对黏结性能的影响,设计了15组45个常温养护条件下的中心拔出试件; 通过中心拔出试验,观察试件在静力荷载作用下的破坏过程、裂缝的产生、试件破坏形态以及黏结应力-滑移曲线特征等.结果表明:高强钢筋与UHPC黏结强度较大,约为48～73 MPa; 与普通混凝土不同的是钢筋与UHPC的黏结强度随着钢筋直径的增加而增加; 黏结强度与保护层厚度成正比,与黏结长度成反比; 保护层厚度对试件破坏模式影响较大,保护层厚度较薄时,试件发生劈裂; 保护层厚度较大时试件发生拔出破坏.钢筋在拔出的过程中黏结应力-滑移曲线与坐标横轴围成的面积较大,表明其耗能能力较强.基于试验结果,结合黏结机理分析提出了黏结强度计算模型以及黏结-滑移本构方程,理论计算结果与试验结果吻合较好.

Pullout test was conducted to investigate the bond characteristics of high strength steel bars embedded in Ultra-High Performance Concrete(UHPC)considering bar diameter,bar embedment length and concrete cover.Measurements included pullout force and slip at free end of the rebar,and crack patterns were monitored and bond failure modes were observed.Some new results had been found in this test.The bond strength increased with an increase in the bar diameter.The thickness of concrete cover had a significant effect on the bond failure type.UHPC had tremendous energy absorb capacity due to the debonding and pullout of steel fibers from the concrete.Analytical models for the evaluation of bond strength and constitute relationship of the bond stress-slip curves are proposed based on the test results,which agree well with the experimental results.

引言
1 试验概况
2 试验结果
3 试验结果分析
4 黏结应力-滑移本构关系
5 黏结强度理论计算
6 结论

表1 钢筋力学性能指标<br/>Tab.1 Mechanical properties of steel bar

表1 钢筋力学性能指标
Tab.1 Mechanical properties of steel bar

图1 试件设计图(单位:mm)<br/>Fig.1 Design of the specimen(unit:mm)

图1 试件设计图(单位:mm)
Fig.1 Design of the specimen(unit:mm)

表2 试验设计<br/>Tab.2 Design of the pull-out test

表2 试验设计
Tab.2 Design of the pull-out test

图2 试验加载装置<br/>Fig.2 Test setup for the pull-out test

图2 试验加载装置
Fig.2 Test setup for the pull-out test

图3 劈裂+拔出破坏试件<br/>Fig.3 Splitting and pullout bond failure mode of the test

图3 劈裂+拔出破坏试件
Fig.3 Splitting and pullout bond failure mode of the test

表3 试验结果
Tab.3 Test results

图4 平均黏结应力-滑移曲线<br/>Fig.4 Average bond stress-slip curves of all groups

图4 平均黏结应力-滑移曲线
Fig.4 Average bond stress-slip curves of all groups

表4 平均黏结应力-滑移曲线与坐标横轴围成的面积<br/>Tab.4 Area under the average bond stress-slip curve for the second batch

表4 平均黏结应力-滑移曲线与坐标横轴围成的面积
Tab.4 Area under the average bond stress-slip curve for the second batch

图5 钢筋直径对黏结强度和峰值滑移的影响<br/>Fig.5 Effect of bar diameter on bond strength and corresponding slip

图5 钢筋直径对黏结强度和峰值滑移的影响
Fig.5 Effect of bar diameter on bond strength and corresponding slip

图6 钢筋直径对平均黏结应力-滑移曲线的影响<br/>Fig.6 Effect of bar diameter on average bond stress-slip curves

图6 钢筋直径对平均黏结应力-滑移曲线的影响
Fig.6 Effect of bar diameter on average bond stress-slip curves

图7 钢筋黏结长度对黏结强度、峰值滑移的影响<br/>Fig.7 Effect of embedment length on bond strength and corresponding slip

图7 钢筋黏结长度对黏结强度、峰值滑移的影响
Fig.7 Effect of embedment length on bond strength and corresponding slip

图8 黏结长度对平均黏结应力-滑移曲线的影响<br/>Fig.8 Effect of embedment length on average bond stress-slip curves

图8 黏结长度对平均黏结应力-滑移曲线的影响
Fig.8 Effect of embedment length on average bond stress-slip curves

图9 保护层厚度对黏结强度和峰值滑移的影响<br/>Fig.9 Effect of concrete cover on bond strength and corresponding slip

图9 保护层厚度对黏结强度和峰值滑移的影响
Fig.9 Effect of concrete cover on bond strength and corresponding slip

图10 保护层厚度对平均黏结应力-滑移曲线影响<br/>Fig.10 Effect of concrete cover on average bond stress-slip curves

图10 保护层厚度对平均黏结应力-滑移曲线影响
Fig.10 Effect of concrete cover on average bond stress-slip curves

表5 计算值与试验值对比<br/>Tab.5 Comparison of calculated values to experimental results

表5 计算值与试验值对比
Tab.5 Comparison of calculated values to experimental results

图11 计算值与试验值比较<br/>Fig.11 Comparison of calculated values with experimental results

图11 计算值与试验值比较
Fig.11 Comparison of calculated values with experimental results

图12 拟合曲线与试验结果对比<br/>Fig.12 Comparison of experimental curves with fitting curves

图12 拟合曲线与试验结果对比
Fig.12 Comparison of experimental curves with fitting curves

表6 劈裂破坏黏结强度计算值与试验值对比<br/>Tab.6 Comparison of calculated bond strengthto experimental results

表6 劈裂破坏黏结强度计算值与试验值对比
Tab.6 Comparison of calculated bond strengthto experimental results

图13 计算值与试验值对比<br/>Fig.13 Comparison of calculated values with experimental results

图13 计算值与试验值对比
Fig.13 Comparison of calculated values with experimental results

图14 理论值与试验值对比分析<br/>Fig.14 Comparison of calculated values to experimental results

图14 理论值与试验值对比分析
Fig.14 Comparison of calculated values to experimental results

图15 理论值与试验值对比分析<br/>Fig.15 Comparison of calculated values to experimental results

图15 理论值与试验值对比分析
Fig.15 Comparison of calculated values to experimental results

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备注

引言

1 试验概况

2 试验结果

3 试验结果分析

4 黏结应力-滑移本构关系

5 黏结强度理论计算

6 结论

期刊信息