The early-age thermal cracking easily generates and severely impairs the durability of concrete.The temperature rising inhibitor(TRI)was utilized to regulate the temperature evolution by controlling the cement hydrati...The early-age thermal cracking easily generates and severely impairs the durability of concrete.The temperature rising inhibitor(TRI)was utilized to regulate the temperature evolution by controlling the cement hydration process.This paper aimed to investigate the pore structure formation and hydration characteristics of cement paste containing TRI by low-field nuclear magnetic resonance.The experiment showed that the T_(2) peak of cement paste shifted from 7.32 ms to 0.23 ms regardless of TRI addition.But the pattern of pore structure formation was changed with TRI addition,that is,the pore structure formation was delayed,and the pore successively shifted to left in two parts.In addition,TRI addition significantly prolonged the duration of gel pore formation and greatly decreased the increase rate of gel water,which implied that TRI introduction hindered the growth of C-S-H,and subsequently decreased the hydration rates and delayed the main hydration peak.Meanwhile,TRI dissolved and diffused rapidly at 40℃,delaying the hydration of cement paste seriously.Moreover,TRI brought about the C-S-H nucleation homogeneous and the ion concentration uniform,which might reduce the localized curvature occurring on the sheet of C-S-H,and then decreased the T_(2) intensity of capillary water and gel water.展开更多
基金Projects(51878245,U1965105) supported by the National Natural Science Foundation of ChinaProject(2017YFB0310100) supported by the National Key R&D Program of ChinaProject(2019CEM001) supported by the State Key Laboratory of High Performance Civil Engineering Materials,China。
文摘The early-age thermal cracking easily generates and severely impairs the durability of concrete.The temperature rising inhibitor(TRI)was utilized to regulate the temperature evolution by controlling the cement hydration process.This paper aimed to investigate the pore structure formation and hydration characteristics of cement paste containing TRI by low-field nuclear magnetic resonance.The experiment showed that the T_(2) peak of cement paste shifted from 7.32 ms to 0.23 ms regardless of TRI addition.But the pattern of pore structure formation was changed with TRI addition,that is,the pore structure formation was delayed,and the pore successively shifted to left in two parts.In addition,TRI addition significantly prolonged the duration of gel pore formation and greatly decreased the increase rate of gel water,which implied that TRI introduction hindered the growth of C-S-H,and subsequently decreased the hydration rates and delayed the main hydration peak.Meanwhile,TRI dissolved and diffused rapidly at 40℃,delaying the hydration of cement paste seriously.Moreover,TRI brought about the C-S-H nucleation homogeneous and the ion concentration uniform,which might reduce the localized curvature occurring on the sheet of C-S-H,and then decreased the T_(2) intensity of capillary water and gel water.
