高强自密实微膨胀钢管混凝土制备及工程应用  

Preparation and application of high-strength self-compacting micro-expansion steel tube concrete

作　　者：周孝军[1] 白时明 李鑫 江俊松[1] 丁庆军[2] ZHOU Xiaojun;BAI Shiming;LI Xin;JIANG Junsong;DING Qingjun(School of Architecture and Civil Engineering,Xihua University,Chengdu 610039,China;State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]西华大学建筑与土木工程学院,四川成都610039 [2]武汉理工大学硅酸盐建筑材料国家重点实验室,湖北武汉430070

出　　处：《混凝土》2023年第10期206-211,共6页Concrete

基　　金：国家自然科学基金(52008340);西华大学自然科学基金重点项目(Z1420603)。

摘　　要：根据简阳沱江特大桥结构特点与主管、缀板管内混凝土灌注工艺及其性能要求,提出了高强自密实微膨胀钢管混凝土配合比设计技术路线。采用商混站原材料,系统研究了胶凝用量、水灰比、砂率、粗骨料级配、膨胀剂掺量等各因素对高强自密实微膨胀钢管混凝土力学性能、工作性能及体积稳定性的影响规律,成功制备出既可泵送又能人工灌注的大流态、补偿收缩和高保坍C50高强自密实微膨胀钢管混凝土。研究结果表明:适宜的胶材体系与水胶比能提升混凝土强度;合理砂率与粗细骨料级配组成可以有效降低混凝土的孔隙率,改善混凝土性能;膨胀剂掺量和砂率都会影响混凝土体积稳定性,微膨胀混凝土宏观体积先膨胀后收缩,最后可稳定于微膨胀状态。采用胶凝材料用量551 kg/m^(3)、0.31水胶比、合理砂率(43%)和粗细骨料级配(组成比例8∶2),试验成功制备出U型箱高度355 mm、V型漏斗时间23 s,3 h坍落/扩展度损失<50 mm,28 d抗压强度为105.1 MPa,28 d膨胀率稳定于112×10-6的高强自密实微膨胀钢管混凝土。研究成果应用于四川简阳沱江特大桥钢管混凝土主拱肋主管与缀板管内混凝土灌注施工,密实度高,工程效果良好。According to the structural characteristics of the Jianyang Tuojiang Special Bridge,the concrete pulling process and the performance requirements of the main and embellished plates,the technical route for the design of the high-strength self-compacting micro-expansion steel tube concrete ratio was proposed.The influence of various factors such as cementitious dosage,water-cement ratio,sand rate,coarse aggregate gradation and admixture of expansion agent on the mechanical properties,workability and volume stability of concrete was systematically studied.C50 high-strength,self-compacting,micro-expansion steel tube concrete that can be both pumped and manually filled was successfully tested.The results of the study show that suitable cementitious material and water-cement ratios improve the strength of concrete.A reasonable sand rate and coarse and fine aggregate grading composition can effectively reduce the porosity of concrete and improve its performance.The amount of expansive agent and sand rate will affect the volume stability of concrete,and volume of micro-expansion concrete firstly expansion and then shrinkage,finally can be stabilized in a slightly expanded state.Using a cementitious material dosage of 551 kg/m^(3),a water-cement ratio of 0.31,a reasonable sand rate(43%)and coarse and fine aggregate gradation(composition ratio 8∶2),the test successfully prepared a U-box height of 355 mm,V-funnel time of 23 s,3 h slump/expansion loss of<50 mm,28 d compressive strength of 105.1 MPa and 28 d expansion rate stable at 112×10-6 high strength self-compacting slightly expanded steel tube concrete.The research results were applied to the construction of concrete pulling in the main arch rib main tube and embellishment plate tube of the Tuojiang Special Bridge,with high compactness and good engineering results.

关 键 词：高性能混凝土 钢管混凝土 自密实 体积稳定性 

分 类 号：TU528.571[建筑科学—建筑技术科学]