MICROSTRUCTURE AND PERMEABILITY CHANGES OF PASTE UNDER CALCITE DEPOSITION AND LEACHING PROCESS
Microsture performance of pastes under calcite deposition and leaching proecess arepresented in this article. From experiments it was found that the penetrable calcite depositedwith the complex function of carhoxylic acid supplied by self healing promoted materials(SHPM) could reduce the permeability and porosity of cement paste. The SHPM is used tocoat on the surface of cementitious materials to reduce the permeability by penetrabledeposition of proliferated calicte from surface to internal matrix. Permeation characteristicsare parallel studied on the samples blended with feasible magnesium salt and curing in dilutecarboxylic acids solution without SHPM coating. The sample coated with SHPM consistingof carboxylic acid with one hydroxyl group per molecule showed lowest permeability andporosity, while the permeability of paste blended with magnesium salt and cured in dilutecarboxylic acidic solution dramatically increase during the leaching period. The calcitemorphologies chelated by three carboxylic acids are compared with Scanning ElectronMicroscopy (SEM) observation. With the increase of the number of hydroxyl group in acarboxylic acid molecular, the deposit calcite particle turn to be more spherical, whichindicated a higher dissolution and more favorable to deposit in lower concentration ofcarboxylic acid. The redistribution of the pore size of the samples after permeation testrevealed the process of calcite dissolution, precipitation and clog in porous cementitiousmaterials. This study is aimed to explore the mechanism of self healing process of carbonatedconcrete in ambient weak acidic saturated environment.
Youkun You Guang Ye Chunxiang Qian Changwen Miao K.van Breugel
Southeast University,Nanjing 211189,P.R.China;Jiangsu Provincial Building Institute,Nanjing 210008,P Delft University of Technology,2628 CN Delft,the Netherlands Southeast University,Nanjing 211189,P.R.China Jiangsu Provincial Building Institute,Nanjing 210008,P.R.China
国际会议
南京
英文
647-656
2008-10-13（万方平台首次上网日期，不代表论文的发表时间）