Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes（Ф68 mm×32 mm,Ф59 mm×29.5 mm and Ф32 mm×16 mm）to study the influence of specimen size on the compre...Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes（Ф68 mm×32 mm,Ф59 mm×29.5 mm and Ф32 mm×16 mm）to study the influence of specimen size on the compression behavior of cement-based materials under high strain rates.The static tests were applied using a universalservo-hydraulic system,and the dynamic tests were applied by a spilt Hopkinson pressure bar（SHPB）system.The experimentalresults show that for mortar and paste specimens,the dynamic compressive strength is greater than the quasi-static one,and the dynamic compressive strength for specimens of large size is lower than those of smallsize.However,the dynamic increase factors（DIF）has an opposite trend.Obviously,both strain rate and size effect exist in mortar and paste.The test results were then analyzed using Weibull,Carpinteriand Ba？ant＇s size effect laws.A good agreement between these three laws and the test results was reached on the compressive strength.However,for the experimentalresults of paste and cement mortar,the size effect is not evident for the peak strain and elastic modulus of paste and cement mortar.展开更多
In order to study the size effect on the AE rate ’a’ value,three kinds of mix ratios were set up by different particle sizes and water cement ratios,45 cement mortar specimens with five different heights were tested...In order to study the size effect on the AE rate ’a’ value,three kinds of mix ratios were set up by different particle sizes and water cement ratios,45 cement mortar specimens with five different heights were tested under axial compression.And the whole damage processes were monitored by full-digital acoustic emission acquisition system,followed by an analysis of mechanical behavior and AE activity.The experimental results show that the height of the cement specimen has significant effects on the compressive strength and the acoustic emission rate ’a’ value,but a slight effect on the accumulated AE hits number,which is analyzed from aspects of failure process of cement mortar specimens.展开更多
基金Funded by the National Natural Science Foundation of China(No.51509078)the Natural Science Foundation of Jiangsu Province(No.BK20150820)
文摘Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes（Ф68 mm×32 mm,Ф59 mm×29.5 mm and Ф32 mm×16 mm）to study the influence of specimen size on the compression behavior of cement-based materials under high strain rates.The static tests were applied using a universalservo-hydraulic system,and the dynamic tests were applied by a spilt Hopkinson pressure bar（SHPB）system.The experimentalresults show that for mortar and paste specimens,the dynamic compressive strength is greater than the quasi-static one,and the dynamic compressive strength for specimens of large size is lower than those of smallsize.However,the dynamic increase factors（DIF）has an opposite trend.Obviously,both strain rate and size effect exist in mortar and paste.The test results were then analyzed using Weibull,Carpinteriand Ba？ant＇s size effect laws.A good agreement between these three laws and the test results was reached on the compressive strength.However,for the experimentalresults of paste and cement mortar,the size effect is not evident for the peak strain and elastic modulus of paste and cement mortar.
基金Funded by the National Natural Science Foundation of China(No.51009058)the Postdoctoral Science Foundation of China(No.2011M501160)
文摘In order to study the size effect on the AE rate ’a’ value,three kinds of mix ratios were set up by different particle sizes and water cement ratios,45 cement mortar specimens with five different heights were tested under axial compression.And the whole damage processes were monitored by full-digital acoustic emission acquisition system,followed by an analysis of mechanical behavior and AE activity.The experimental results show that the height of the cement specimen has significant effects on the compressive strength and the acoustic emission rate ’a’ value,but a slight effect on the accumulated AE hits number,which is analyzed from aspects of failure process of cement mortar specimens.
