约束混凝土和素混凝土抗冻性能对比研究  

Comparatuie investugation on anti-freeze behavior of confined and plain concrete

作　　者：张俊萌[1] 方从启[1] 段桂珍[1] 

机构地区：[1]上海交通大学船舶海洋与建筑工程学院,上海200240

出　　处：《混凝土》2014年第3期25-29,共5页Concrete

基　　金：铁道部科技研究开发计划项目(J2011G003);国家自然科学基金项目(51178264)

摘　　要：为了对比分析素混凝土和约束混凝土抗冻性能差异，对不同配合比的素混凝土块和钢筋混凝土柱进行0、20、40、60、100、120次的冻融腐蚀试验。作为第三部分，主要总结约束混凝土试验和素混凝土试验，分析两者抗冻性能差异，主要从抗压强度损失变化、破坏形态、冻融破坏机理以及冻融损伤预测模型方面进行对比。对比结果显示：在冻融循环过程中，约束混凝土抗压强度呈三次曲线趋势下降，中间有明显平台阶段，而素混凝土抗压强度呈二次抛物线趋势逐步下降。粉煤灰对抗压强度影响较大，不掺粉煤灰的约束混凝土的抗压强度远远大于素混凝土，抗压强度损失差异达30％-40％；掺15％粉煤灰对约束混凝土和素混凝土抗压强度均不利，但对约束混凝土的影响更大，明显减小两者抗压强度差异。水灰比对抗压强度影响较小，但使用粉煤灰时，对于素混凝土应降低水灰比，而约束混凝土宜提高水灰比。由于箍筋的约束作用，约束混凝土破坏过程以及机理和素混凝土有很大的差异。因此用素混凝土的抗冻性能来评估实际钢筋混凝土抗冻性能是不合理的，有必要建立实用的约束混凝土的抗冻性能预测模型。In order to study the antifreeze performance difference of confined concrete and plain concrete by contrast, different material ratio of plain concrete cubic blocks and confined concret columns were tested under freeze-thaw cycle of different numbers as 0,20,40,60,100 and 120 times.As the third part, this paper mainly summarized the experiment of confined concrete and plain concrete, the difference of antifreeze performance between plain concret and confined concret are analyzed, mainly from the loss of compressive strength, failure pattern, mechanism of freeze-thaw damage and freeze-thaw damage prediction model.Comparison results shows that, in the process of freezing and thawing cycle, the compressive strength of confined concrete cubic curve trend down, there was a obvious plat- form stage, while compressive strength of plain concrete gradually decreased as a parabola.Compared with water cement ratio, Fly ash had a greater influence on the compressive strength loss of both concret.without admixture of fly ash, confined concrete compressive strength is much greater than the plain concrete and the compressive strength loss difference came to 30%-40% ;admixture of 15% fly ash had obvi- ous disadvantage to compressive strength of confined concrete and plain concrete, but a greater impact of confined concrete, reduce the compressive strength signifi cantly.Compressive strength influenced by water cement ratio was small, but when using fly ash, for plain con- crete it is good to reduce the water cement ratio ,while for confined concrete it is good to improve the water-cement ratio.Due to the effect of constraints of the stirrup, failure process and mechanism of confined concrete and plain concrete has very big difference.So using antifreeze performance of plain concrete performance to evaluate actual antifreeze performance of reinforced concrete is unreasonable, it is necessary to establish practical antifreeze performance prediction model of confined concrete.

关 键 词：约束混凝土 素混凝土 冻融循环 抗压强度 破坏机理 

分 类 号：TU528.01[建筑科学—建筑技术科学]