预制C50盖梁混凝土防裂性能研究  

Anti-crack performance improvement of concrete for prefabricated C50 bent cap concrete

作　　者：张丰[1,2] 祝烨然 白银[1,2] 李洁 杨恒[1,2] 唐建辉 吕乐乐 ZHANG Feng;ZHU Yeran;BAI Yin;LI Jie;YANG Heng;TANG Jianhui;LYU Lele(Nanjing Hydraulic Research Institute,Nanjing 210029,China;The National Key Laboratory of Water Disaster Prevention,Nanjing 210029,China;Nanjing R&D High-Tech Co.Ltd.,Nanjing 210024,China)

机构地区：[1]南京水利科学研究院,江苏南京210029 [2]水灾害防御全国重点实验室,江苏南京210029 [3]南京瑞迪高新技术有限公司,江苏南京210024

出　　处：《新型建筑材料》2024年第11期1-6,共6页New Building Materials

基　　金：国家重点研发计划项目(2020YFC1511902);国家自然基金重点项目(51739008);江苏省自然科学基金项目(BK20201125);南京市交通科技项目(G312NJ-KTYJ7)。

摘　　要：通过测试预制盖梁混凝土的力学、变形、早期抗裂性能,并采用三维仿真软件分析其内部温度场、应力场的分布规律,研究掺入膨胀剂、内养护剂对预制盖梁混凝土防裂性能的提升效果。结果表明:预制C50盖梁混凝土早期强度发展快,但干缩变形大,开裂风险高。复掺5%膨胀剂+0.1%内养护剂时,7~90 d抗压强度较基准组提高了4%~9%、抗拉强度、抗拉弹性模量提高了2%~6%,干缩变形减小了10%~19%,毛细孔负压峰值降低,峰值出现时间延后,平板开裂试验至48 h未见明显裂缝,虽然对温度场影响不大,但能降低混凝土应力集中时的应力峰值,最大拉应力出现时间较基准组延后11 h,抗裂安全系数增大至0.58。但混凝土开裂风险仍较大,需通过其他措施进一步减小开裂风险。This study tests the mechanical properties,deformation,and early anti-cracking performance of precast beam cap concrete.Using 3D simulation software,it analyzes the distribution of internal temperature and stress fields,focusing on the improvement effect of expansive agent and internal curing agent on the crack resistance of precast beam cap concrete.Results indicate that precast C50 beam cap concrete develops early strength rapidly but exhibits significant drying shrinkage,leading to a high risk of cracking.With the addition of 5%expansive agent and 0.1%internal curing agent,compressive strength increased by 4%~9%from 7~90 d,while tensile strength and tensile modulus of elasticity rose by 2%~6%.Drying shrinkage deformation decreased by 10%~19%,and the peak negative pressure of capillary pores was reduced with a delayed peak occurrence.No visible cracks appeared in the flat plate cracking test until 48 h.Although the agents had minimal impact on the temperature field,they reduced the stress peak during stress concentration,delaying the maximum tensile stress by 11 hours compared to the control group,and increasing the crack resistance safety factor to 0.58.However,the risk of cracking remains significant,necessitating further measures to mitigate it.

关 键 词：装配式混凝土 毛细孔负压 膨胀剂 内养护剂 仿真分析 

分 类 号：TU528[建筑科学—建筑技术科学]