保水剂对墩身混凝土性能影响研究  

Study on the influence of water retaining agents on performance of pier concrete

作　　者：贾胜利 Jia Shengli

机构地区：[1]中铁十八局集团有限公司,天津300222

出　　处：《现代城市轨道交通》2022年第6期72-77,共6页Modern Urban Transit

摘　　要：墩身混凝土施工、养护过程中时常出现“砂线”问题,文章提出调整胶凝体系的同时掺加保水剂,通过对比改性后混凝土的泌水率、坍落度、含气量、抗压强度、电通量值以及抗氯离子扩散系数得出如下结论:①粉煤灰-矿粉-水泥胶凝体系保水剂掺量0.05%(B10)泌水率最低,相当于水泥胶凝体系(B0)的29.88%,当保水剂掺量大于0.05%时,坍落度值、含气量已不满足于墩身混凝土设计要求;②强度最优配比为B10,其56天强度可到达59.4 MPa,相当于B0的123.24%;③对比保水剂掺量0.05%时,水泥胶凝体系(B3)、粉煤灰-水泥胶凝体系(B6)、矿粉-水泥胶凝体系(B8)、粉煤灰-矿粉-水泥胶凝体系(B10)在56天标准养护条件下电通量、抗氯离子扩散系数发展规律,得出不同胶凝体系发展趋势为B3>B6>B8>B10。To solve the problem of"sand line"in the construction and maintenance of the pier concrete,the study proposed to adjust the cementitious components and add water retaining agent at the same time.By comparing the bleeding rate,slump constant,air content,compressive strength,electric flux value and anti-chloride diffusion coefficient of modified concrete,the conclusions were as follows:①Fly ash-slag-cement cementitious component system with 0.05%of water retaining agent(B10)had the lowest bleeding rate,compared with 29.88%of cement cementitious component system(B0).When the amount was greater than 0.05%,the slump constant value and air content were no longer satisfied with the design requirements of the pier concrete;②The optimal strength ratio was B10,and its 56d strength can reach 59.4 MPa,which was 123.24%compared to B0.③When the dosage of water retaining agent was 0.05%,the development trend of electric flux and anti-chloride diffusion coefficient of a cement cementitious component system(B3),fly ash-cements cementitious component system(B6),mineral powder cement cementitious component system(B8)and fly ash-mineral powder-cement cementitious component system(B10)under 56d standard curing conditions,the development trend is B3>B6>B8>B10.

关 键 词：高速铁路 墩身混凝土 砂线 保水剂 泌水率 电通量值 抗氯离子扩散系数 

分 类 号：TU528.45[建筑科学—建筑技术科学]