| 摘要: |
| 为改善活性粉末混凝土(RPC)材料的收缩性能，在RPC配合比基础上掺入碎石，设计了10片改进RPC普通混凝土(NC)叠合梁、1片纯NC梁和2个改进RPC收缩试块.采用振弦式应变计和应力计分别测量了包含蒸汽养护阶段在内的改进RPC NC叠合梁跨中截面混凝土的收缩应变及梁底纵向钢筋的收缩应力，同时与纯NC梁的收缩应变量进行了对比分析.结果表明：改进RPC材料的收缩应变量仅为650×10-6～660×10-6；纵向钢筋配筋率、RPC高度、上部NC等级等因素对叠合梁跨中截面混凝土的收缩发展具有重要影响；由RPC NC叠合梁收缩引起的梁底纵向钢筋应力为40～63MPa，而由纯NC梁收缩引起的梁底钢筋应力为40MPa左右；改进RPC材料的收缩应变量仅为同条件下原RPC收缩应变量的37%，说明碎石的掺入可使RPC收缩应变量大大减小，同时也降低了RPC的造价，有利于RPC材料在工程中的推广应用. |
| 关键词: 活性粉末混凝土（RPC） 普通混凝土（NC） 叠合梁 收缩性能 |
| DOI：10.3969/j.issn.1007 9629.2017.03.013 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(51278040)；教育部中央高校基本科研业务费专项资金资助项目(2014YJS106) |
|
| Shrinkage Property of Reactive Powder Concrete Composite Beam |
|
LI Wangwang, JI Wenyu, AN Mingzhe
|
|
School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
|
| Abstract: |
| The shrinkage property of reactive powder concrete(RPC) can be improved by mixing coarse aggregate. 10 RPC normal concrete(NC) composite beams, 1 NC beam and 2 improved RPC specimens were designed on the basis of optimizing the mixture proportion. The shrinkage strain of RPC NC composite beam at mid span section and the shrinkage stress of longitudinal steel bars in the bottom of beams including steam curing process were investigated by using vibrating wire extensometer and stress meter. The results show that the total shrinkage strain of improved RPC material is 650×10-6660×10-6. All the influencing factors including the ratio of longitudinal reinforcement, height of RPC, concrete grade of NC, etc. have great effects on the shrinkage of composite beam at mid span section, which is compared with the shrinkage of NC beam. The stress of longitudinal reinforcement was 4063MPa in the bottom of RPC NC composite beams. The stress of longitudinal reinforcement is about 40 MPa in the bottom of NC beam. The results show that the shrinkage of improved RPC material is only 37% of normal RPC. It is indicated that the incorporation of gravel can greatly reduce the shrinkage of RPC and reduce the cost simultaneously. And this will promote the application of RPC in engineering. |
| Key words: reactive powder concrete（RPC） normal concrete（NC） composite beam shrinkage property |
