混凝土在化学腐蚀和冻融循环共同作用下的强度变化  

Strength Development of Concrete Subjected to Combined Actions of Freezing-thawing Cycles and Chemical Attack

作　　者：余红发[1] 孙伟[2] 李美丹[3] 

机构地区：[1]南京航空航天大学土木工程系,南京210016 [2]东南大学材料科学与工程系,南京210096 [3]沈阳建筑大学材料科学与工程学院,辽宁沈阳110168

出　　处：《沈阳建筑大学学报（自然科学版）》2006年第4期588-591,642,共5页Journal of Shenyang Jianzhu University：Natural Science

基　　金：江苏省自然科学基金前期预研项目(BK2005216)

摘　　要：目的为研究混凝土的抗DDF破坏问题．方法测定了普通混凝土（OPC）、引气混凝土（APC）、不掺活性掺合料的高强混凝土（HSC）和复合掺加活性掺合料的高性能混凝土（HPC）在（化学腐蚀＋冻融循环）双重破坏因素（DDF）作用下的强度变化．结果OPC在盐湖卤水DDF作用下的破坏比较快，APC在青海和新疆盐湖卤水的1250次DDF作用下的抗压强度甚至能够提高23％～33％．HSC和HPC在盐湖卤水的1550次DDF作用下具有很高的强度，且HPC的抗冻性明显优于HSC．延长混凝土的标准养护龄期，既不能阻止OPC在盐湖卤水DDF作用下发生破坏，也不能明显改善HSC在盐湖卤水DDF作用下的强度，但是却能大大提高APC的DDF强度，对于提高HPC在盐湖卤水DDF作用下的抗折强度也极其有效．进一步的研究指出，混凝土在DDF作用下的强度基本上随着冻融循环次数的增加而降低。而且OPC和APC的冻融强度损失明显高于HSC和HPC．结论HSC、HPC同时适应于青海和新疆等恶劣的盐湖卤水环境．Strength development of Ordinary Portland cement concrete （OPC）, air - entrained Portland cement concrete （APC）, high strength concrete （HSC） without mineral admixture and high performance concrete （HPC） mixed with mineral admixtures, subjected to the double damage factors （DDF）, which were combined actions of freezing - thawing cycles and chemical attack, were investigated. Results show that OPC is easily damaged when subjected to the DDF, while APC shows a compressive strength increases up to 23 %- 33 % when subjected to 1250 DDF cycles in Qinghai or Xinjiang bittern. Though both HSC and HPC exhibit high compressive strength when subjected to 1550 DDF cycles in bitterns, HPC show a freezing - thawing durability much better than HSC. When concretes subjected to bittern DDF, prolonged curing time have no effect either on preventing OPC from damaging nor on improving strength of HSC, but it does work on increasing compressive strength of APC and flexural strength of HPC. Further research indicates that strength of concretes subjected to DDF decreased alone with the increasing of freezing - thawing cycles, and the strength losing of OPC and APC is more evident than those of HSC and HPC. It can be concluded that both HSC and HPC are applicable to Qinghai or Xinjiang salt lake bitterns.

关 键 词：高强混凝土 高性能混凝土 冻融循环 化学腐蚀 抗压强度 抗折强度 

分 类 号：TU528[建筑科学—建筑技术科学]