Thermoporometry(TPM) is a calorimetric-based technique for characterizing pore structure according to the freezing and melting point depression of liquid confined in pores which attributes to a varying phase-transitio...Thermoporometry(TPM) is a calorimetric-based technique for characterizing pore structure according to the freezing and melting point depression of liquid confined in pores which attributes to a varying phase-transition free energy by interface curvature.TPM has demonstrated an emerging success in applications for determining the mesopores of cement-based materials in recent decades.To improve its resolution and accuracy,this paper discussed these factors which show a great influence on the baseline heat flow and the derived pore structure using two molecular sieves with discontinuous size for calibration,referring to the sample handling,the mass of sample and the varying temperature.The pore size distributions of ordinary and high-strength concrete by TPM were favorably compared to the results taken by nitrogen adsorption/desorption(NAD) and mercury intrusion porosimetry(MIP).The results illustrated that both the accuracy and resolution improve with the decreasing cooling/heating rate until 1 °C/min;however,if the rate is too slow,it can lead to an unstable result.The mass of the sample tested has much less an effect on the accuracy when it increases to more than 30 mg.TPM is demonstrated to be more accurate to characterize the mesopores with the size bigger than 4 nm as compared to NAD and MIP.展开更多
基金supported by the National Basic Research Program(973)of China(No.2011CB013805)the National Natural Science Foundation of China(Nos.51278360,51078269,and 51308407)+1 种基金the National Key Project of Scientific and Technical Supporting Programs of China(No.2011BAE14B06)the Open Funding of the Key Laboratory of Advanced Civil Engineering Materials of the Ministry of Education,Tongji University(No.201303),China
文摘Thermoporometry(TPM) is a calorimetric-based technique for characterizing pore structure according to the freezing and melting point depression of liquid confined in pores which attributes to a varying phase-transition free energy by interface curvature.TPM has demonstrated an emerging success in applications for determining the mesopores of cement-based materials in recent decades.To improve its resolution and accuracy,this paper discussed these factors which show a great influence on the baseline heat flow and the derived pore structure using two molecular sieves with discontinuous size for calibration,referring to the sample handling,the mass of sample and the varying temperature.The pore size distributions of ordinary and high-strength concrete by TPM were favorably compared to the results taken by nitrogen adsorption/desorption(NAD) and mercury intrusion porosimetry(MIP).The results illustrated that both the accuracy and resolution improve with the decreasing cooling/heating rate until 1 °C/min;however,if the rate is too slow,it can lead to an unstable result.The mass of the sample tested has much less an effect on the accuracy when it increases to more than 30 mg.TPM is demonstrated to be more accurate to characterize the mesopores with the size bigger than 4 nm as compared to NAD and MIP.
