（1 内蒙古科技大学土木工程学院， 包头 014010； 2 内蒙古科大工程项目管理有限责任公司， 包头  014010;  3 包头铝业集团建安工程有限责任公司， 包头 014046)

［摘要］对经过0次、50次、100次、150次、200次冻融循环的再生混凝土（粗骨料取代率100%）进行拉拔试验研究，以钢筋直径16mm和20mm、锚固长度5d和10d为变动因素，分析冻融循环次数对再生混凝土立方体抗压强度、极限拉拔荷载和极限黏结应力的影响，并采用钢筋开槽内贴应变片的方法，研究了不同冻融循环次数后钢筋锚固段内钢筋应变、局部黏结应力和极限黏结应力平均值-滑移的分布规律。结果表明，冻融循环后再生混凝土抗压强度下降，极限荷载和极限黏结应力平均值随着冻融循环次数的增加而逐渐减小；随着冻融循环次数的增加，荷载作用下钢筋应变沿锚固长度的变化曲线趋于平缓，局部黏结应力首先在加载端附近出现应力峰值，沿锚固长度逐渐向自由端传递，总体呈现减小的趋势。

［关键词］再生混凝土； 冻融循环； 拉拔试验； 黏结应力； 黏结应力-滑移

中图分类号：TU375文献标识码：A文章编号：1002-848X(2018)09-0097-06

Pullout tests research on steel bars and recycled concrete after freeze-thaw cycles

Wang Chenxia1, Tang Leijie1, Zhang Zhanbiao2, Wang Jianjun3, Cao Fubo1

(1 School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China; 2 Inner Mongolia Keda Project Management Co.,  Ltd.,  Baotou 014010, China; 3 Baotou Aluminium Group Construction Co.,  Ltd.,  Baotou 014046, China)

Abstract:The pullout test research was carried out on recycled concrete containing 100% of recycled coarse aggregate under 0, 50, 100, 150 and 200 times of freeze-thaw cycles. Anchorage lengths of 5d and 10d of steel bar with diameters of 16mm and 20mm were taken as two variable factors to analyze influences of times of freeze-thaw cycles on cubic compressive strength, ultimate pullout load and ultimate bond stress. By embedding strain-gauge inside steel rebar, the steel bar strain, local bond stress and distribution laws of ultimate average bond stress-slip in steel bar anchorage section after different freeze-thaw cycles were studied. The test results show that the compressive strength of recycled concrete descends during the process of freeze-thaw cycle, and the ultimate  load and ultimate average bond stress decrease with the increase of freeze-thaw cycles. The strain curve is flat with the increase of freeze-thaw cycles along the anchorage position under the breaking load. The local bond stress peak first appears near the loading end, and gradually moves to the free end, featuring the trend of decrease in general.

Keywords:recycled concrete; freeze-thaw cycle; pullout test; bond stress; bond stress-slip

*内蒙古自治区自然科学基金项目(2016MS0547)，内蒙古自治区高等学校科学研究项目(NJZY159)。

通讯作者：曹芙波,博士,教授, Email: caofubo@imust.cn。