改善新老混凝土界面粘结性能的措施研究

Experimental Study on the Methods to Improve Interfacial Bonding Behavior Between Existing Concrete and Attached Concrete

通过16组共48个100 mm×100 mm×100 mm 4种纤维混凝土与既有混凝土粘结的立方体试件劈拉试验,研究了新混凝土中纤维种类、纤维掺量对粘结试件劈拉性能的影响。结果表明各种纤维的加入总体上均有利于新老混凝土粘结性能的提高,效果最佳的是碳纳米管,其次是聚丙烯腈纤维,然后是玄武岩纤维和钢纤维。通过64组共192个100 mm×100 mm×100 mm纤维增强聚合物改性混凝土与既有混凝土粘结的立方体试件劈拉试验,研究了新混凝土中纤维种类、纤维与聚合物掺量组合对粘结试件劈拉性能的影响;苯丙乳液的复合掺入总体上可进一步提高新老混凝土的粘结劈拉强度;各种纤维与苯丙乳液复掺时,均存在一个苯丙乳液掺量的最佳值。

Splitting testings on forty eight 100 mm × 100 mm × 100 mm concrete specimens combined by two parts were conducted to figure out efficient methods to improve the interfacial bonding behavior between existing concrete and attached concrete during retrofitting. The attaching concrete was incorporated with four different kinds of fibers,which were stell fiber,polyacrylonitrile fiber,basalt fiber and carbon nano-tube,respectively. The effects of different fiber and its proportion on bonding behavior were investigated. It was shown that the bonding behavior was improved when the attaching concrete incorporated with fiber. Those incorporated with carbon nano-tube performed best,the following one was polyacrylonitrile fiber,and then basalt fiber and steel fiber in order. Furthermore,splitting testings on 192 extra specimens,in which the attaching parts were incorporated with fiber and styrene-acrylic emulsion,were carried out to study the interfacing bonding behavior. The effects of different fibers,the content of styrene-acrylic emulsion and the proportion of fibers were evaluated according the testing results. Incorporating styrene-acrylic emulsion to the attached concrete generally showed better performance than those without styrene-acrylic emulsion. The best content proportion for both fibers and styrene-acrylic emulsion was pointed out according to the testing results.