A novel crystal nucleus-based cement-hardening accelerator was evaluated using various mortar and segment concrete experiments.The mechanism of hardening acceleration was investigated via hydration temperature variati...A novel crystal nucleus-based cement-hardening accelerator was evaluated using various mortar and segment concrete experiments.The mechanism of hardening acceleration was investigated via hydration temperature variation analysis,hydration degree analysis,X-ray diffraction(XRD)and scanning electron microscopy(SEM).In the presence of accelerator,the fluidity loss of mortar was increased after 30 minuites,and a coagulation was also observed.Moreover,based on the image of SEM,the formation of C-S-H gels was enhanced in the early hydration.As a result,the hardening accelerator could significantly boost the early strength of concrete,especially within one day of pouring,and shorten steam curing time to meet the demolding strength.展开更多
Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polyca...Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polycarboxlic series high range water reduce agent and sodium sulfate hardening accelerating agent. Two kinds of curing condition, namely steam curing condition and standard curing condition, are adopted. The result shows that HPC, added with polycarboxlic series of high performance water reducer, has high workability and strength, while sodium sulfate accelerating agent causes poor workability and low strength. Thus for vapor-cured HPC and its formulations, naphthalene series high range water reducing agent with less sodium sulfate should be given pri- ority. Therefore, the differences of curing conditions should be considered when selecting HPC admixtures.展开更多
基金Funded by Star Program(No.1804QB1403200)from Science and Technology Commission of Shanghai Municipality。
文摘A novel crystal nucleus-based cement-hardening accelerator was evaluated using various mortar and segment concrete experiments.The mechanism of hardening acceleration was investigated via hydration temperature variation analysis,hydration degree analysis,X-ray diffraction(XRD)and scanning electron microscopy(SEM).In the presence of accelerator,the fluidity loss of mortar was increased after 30 minuites,and a coagulation was also observed.Moreover,based on the image of SEM,the formation of C-S-H gels was enhanced in the early hydration.As a result,the hardening accelerator could significantly boost the early strength of concrete,especially within one day of pouring,and shorten steam curing time to meet the demolding strength.
基金Supported by the National Basic Research Programe of China("973"Program)(2009CB623203)the Construction Department of Zhejiang Province Foundation(1006)+1 种基金the Education Department of Zhejiang Province Foundation(Y200909029)the Doctoral Innovation Foundation of Nanjing University of Aeronautics andAstronautics(BCXJ07-04)~~
文摘Influences of admixtures on the workability and strength of high performance concrete （HPC） are in- vestigated. The types of investigated admixtures include naphthalene series high range water reducing agent, polycarboxlic series high range water reduce agent and sodium sulfate hardening accelerating agent. Two kinds of curing condition, namely steam curing condition and standard curing condition, are adopted. The result shows that HPC, added with polycarboxlic series of high performance water reducer, has high workability and strength, while sodium sulfate accelerating agent causes poor workability and low strength. Thus for vapor-cured HPC and its formulations, naphthalene series high range water reducing agent with less sodium sulfate should be given pri- ority. Therefore, the differences of curing conditions should be considered when selecting HPC admixtures.
