A theoretical calculation method of the axial compressive strength of a high strength concrete with fibre reinforced plastics (FRP) constraint is proposed. It is shown by test verification that the FRP strength devoti...A theoretical calculation method of the axial compressive strength of a high strength concrete with fibre reinforced plastics (FRP) constraint is proposed. It is shown by test verification that the FRP strength devotion factor used for this method is in accordance with actual conditions. FRP is not up to the ultimate strength when the concrete reaches the ultimate strength, whose strength devotion factor is in the range of 0.28 to 0.59, which is related to an elastic modulus. The method can be used to estimate axial compressive strength of the concrete strengthened with FRP. The theoretical strength is 10% to 30% higher than the measured one. The deviation comes mainly from a non-ideal bonding condition of FRP-concrete interfaces and discrete property of the testing data of compressive strength.展开更多
The effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn(in wt.%)heat-resistant alloy was investigated by microstructure observation and tensile test.A great number of ...The effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn(in wt.%)heat-resistant alloy was investigated by microstructure observation and tensile test.A great number of fine needle-like RE-rich phases are observed in the alloys with RE addition. Solutionizing treatment does not change their morphologies and sizes, indicating that they have good thermal stability. The addition of RE totally alters the solidification process of eutectic CruAl2 phase, from network-like phase in the form of segregation at the final eutectic grain boundaries to discretely blocky phase growing on the hair-filamentous RE-rich needles. In the alloys with Ce addition, blocky CuAl2, particulate Al15Mn3Si2 and needle-like RE-rich needle phases grow together, but they did not occur in the alloy with only La addition. The addition of RE does not considerably improve the strength of the alloy at high temperatures. The formation of RE-rich phases also does not significantly alter the originating and propagating of micro-cracks in the alloy during tensile test.展开更多
The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soi...The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.展开更多
Nowadays, technologies in construction field have offered several kinds of chemical admixtures, which offer different behaviors at the fresh state of the batch and by consequence, it is resulted with different mechani...Nowadays, technologies in construction field have offered several kinds of chemical admixtures, which offer different behaviors at the fresh state of the batch and by consequence, it is resulted with different mechanical behaviors at the solid state of the mix. This study focused on the behavior of a new kind of admixture at fresh and solid states. Currently, the concrete material has become a very expensive material because the high price mostly of aggregates, representing the three quarters of the concrete components. By consequence, it costs money and on the other hand, it produces a lot of wastes. The main aspect which guides this study is to make a kind of concrete based mainly on local material and sustainable concrete material （SCM or waste material）, which is one very abundant material in quality and quantity, under the current tendency the results obtained in this study summarize up the importance of the temperature during the development of the mechanical characteristics of mortar, mainly on compressive strength at age of 28 days. This is in the case of the addition of limestone crushed additive by percentage of substitution.展开更多
文摘A theoretical calculation method of the axial compressive strength of a high strength concrete with fibre reinforced plastics (FRP) constraint is proposed. It is shown by test verification that the FRP strength devotion factor used for this method is in accordance with actual conditions. FRP is not up to the ultimate strength when the concrete reaches the ultimate strength, whose strength devotion factor is in the range of 0.28 to 0.59, which is related to an elastic modulus. The method can be used to estimate axial compressive strength of the concrete strengthened with FRP. The theoretical strength is 10% to 30% higher than the measured one. The deviation comes mainly from a non-ideal bonding condition of FRP-concrete interfaces and discrete property of the testing data of compressive strength.
基金Project(BM2007204)supported by the Jiangsu Key Laboratory of Advanced Metallic Materials,ChinaProject(2242016K40011)supported by the Fundamental Research Funds for the Central Universities,China
文摘The effect of RE addition on solidification process and high-temperature strength of Al-12%Si-4%Cu-1.6%Mn(in wt.%)heat-resistant alloy was investigated by microstructure observation and tensile test.A great number of fine needle-like RE-rich phases are observed in the alloys with RE addition. Solutionizing treatment does not change their morphologies and sizes, indicating that they have good thermal stability. The addition of RE totally alters the solidification process of eutectic CruAl2 phase, from network-like phase in the form of segregation at the final eutectic grain boundaries to discretely blocky phase growing on the hair-filamentous RE-rich needles. In the alloys with Ce addition, blocky CuAl2, particulate Al15Mn3Si2 and needle-like RE-rich needle phases grow together, but they did not occur in the alloy with only La addition. The addition of RE does not considerably improve the strength of the alloy at high temperatures. The formation of RE-rich phases also does not significantly alter the originating and propagating of micro-cracks in the alloy during tensile test.
文摘The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.
文摘Nowadays, technologies in construction field have offered several kinds of chemical admixtures, which offer different behaviors at the fresh state of the batch and by consequence, it is resulted with different mechanical behaviors at the solid state of the mix. This study focused on the behavior of a new kind of admixture at fresh and solid states. Currently, the concrete material has become a very expensive material because the high price mostly of aggregates, representing the three quarters of the concrete components. By consequence, it costs money and on the other hand, it produces a lot of wastes. The main aspect which guides this study is to make a kind of concrete based mainly on local material and sustainable concrete material （SCM or waste material）, which is one very abundant material in quality and quantity, under the current tendency the results obtained in this study summarize up the importance of the temperature during the development of the mechanical characteristics of mortar, mainly on compressive strength at age of 28 days. This is in the case of the addition of limestone crushed additive by percentage of substitution.
