The influence of steel slag,a by-product from the processing of iron to steel,on the hydration of cement during the hydration process of complex binder was studied by calorimetry,X-ray diffraction analysis,and Ca(OH)2...The influence of steel slag,a by-product from the processing of iron to steel,on the hydration of cement during the hydration process of complex binder was studied by calorimetry,X-ray diffraction analysis,and Ca(OH)2 content determination.The results show that steel slag and cement affect each other’s hydration by changing the hydration environment.Steel slag does not react with the hydration products of cement.The dormant period of cement-steel slag complex binder during the hydration is longer than that of cement.The more the adding amount of steel slag is,the longer the dormant period of complex binder will be.The steel slag decreases the early hydration rate of cement.This phenomenon is more obvious with the increment of steel slag addition.However,the steel slag can promote the hydration degree of cement at later ages and the promoting effect becomes more obvious with the increment of steel slag addition and the hydration ages.展开更多
The characteristics of C-S-H gel in hardened Portland cement pastes and complex binder pastes with ground granulated blast furnace slag were investigated with nanoindentation. The composition of C-S-H gel was analysed...The characteristics of C-S-H gel in hardened Portland cement pastes and complex binder pastes with ground granulated blast furnace slag were investigated with nanoindentation. The composition of C-S-H gel was analysed with SEM-EDS. The obtained results showed that the volume fraction of LD C-S-H gradually reduced and the volume fraction of HD C-S-H increased with the prolongation of hydration age. Most of the C-S-H gel produced at later age was HD C-S-H. The volume fraction of HD C-S-H increased as the fraction of slag in complex binder pastes increased, suggesting that HD C-S-H was mainly in the hydration products of slag. The chemichal compositions of the two types of C-S-H gel were simlar, meaning that formation and transformation of the two types of C-S-H gel were not affected by their Ca/Si ratio.展开更多
Regular elemental powders were used in warm flow compaction instead of the expensive micron-sized powders to fabricate cross-shaped parts. Debinding behaviors,sintering properties and shape consistency of the sintered...Regular elemental powders were used in warm flow compaction instead of the expensive micron-sized powders to fabricate cross-shaped parts. Debinding behaviors,sintering properties and shape consistency of the sintered parts were studied. Binder removal was accomplished by heating green compacts at intermediate temperatures with optimal heating rates until the debinding temperature was reached. Results show that by controlling debinding process,complex parts with good shape consistence can be obtained by warm compaction of binder-treated powder. Fine and shiny surface was obtained and no surface defect can be observed for sintered parts debinded at 2 ℃/min,while defect can be observed in sintered parts debinded at 4 ℃/min.展开更多
The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describ...The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describe the impact of aggregate on the adhesiveness phenomena is the zeta potential. In this study, the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). The results showed that aggregate with high percentage of silica have higher zeta potential than aggregate with low percentage of silica. The development of a zeta potential predictive model showed a strong sensitivity to silica. The results of the complex modulus tests showed that Hot Mixture Asphalt (HMA) mixed with aggregate containing high silica contents gave better results than those mixed with aggregates containing low percentage of silica. The dynamic modulus predictive models of HMA developed shows that it is the properties of bitumen that influence more. However, the effect of silica although low, is very marked at low temperatures and high frequencies.展开更多
基金supported by the Beijing Natural Science Foundation(Grant No.8100001)the National Basic Research Program of China("973"Project)(Grant No.2009CB623106)
文摘The influence of steel slag,a by-product from the processing of iron to steel,on the hydration of cement during the hydration process of complex binder was studied by calorimetry,X-ray diffraction analysis,and Ca(OH)2 content determination.The results show that steel slag and cement affect each other’s hydration by changing the hydration environment.Steel slag does not react with the hydration products of cement.The dormant period of cement-steel slag complex binder during the hydration is longer than that of cement.The more the adding amount of steel slag is,the longer the dormant period of complex binder will be.The steel slag decreases the early hydration rate of cement.This phenomenon is more obvious with the increment of steel slag addition.However,the steel slag can promote the hydration degree of cement at later ages and the promoting effect becomes more obvious with the increment of steel slag addition and the hydration ages.
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2009CB623106)the National Natural Science Foundation of China (Grant No. U1134008)
文摘The characteristics of C-S-H gel in hardened Portland cement pastes and complex binder pastes with ground granulated blast furnace slag were investigated with nanoindentation. The composition of C-S-H gel was analysed with SEM-EDS. The obtained results showed that the volume fraction of LD C-S-H gradually reduced and the volume fraction of HD C-S-H increased with the prolongation of hydration age. Most of the C-S-H gel produced at later age was HD C-S-H. The volume fraction of HD C-S-H increased as the fraction of slag in complex binder pastes increased, suggesting that HD C-S-H was mainly in the hydration products of slag. The chemichal compositions of the two types of C-S-H gel were simlar, meaning that formation and transformation of the two types of C-S-H gel were not affected by their Ca/Si ratio.
基金Projects(50574041, 50325516) supported by the National Natural Science Foundation of Chinaprojects(2006Z1-D6081, 06105411) supported by Guangdong Science and Technologyproject (NCET-05-0739) supported by NCET
文摘Regular elemental powders were used in warm flow compaction instead of the expensive micron-sized powders to fabricate cross-shaped parts. Debinding behaviors,sintering properties and shape consistency of the sintered parts were studied. Binder removal was accomplished by heating green compacts at intermediate temperatures with optimal heating rates until the debinding temperature was reached. Results show that by controlling debinding process,complex parts with good shape consistence can be obtained by warm compaction of binder-treated powder. Fine and shiny surface was obtained and no surface defect can be observed for sintered parts debinded at 2 ℃/min,while defect can be observed in sintered parts debinded at 4 ℃/min.
文摘The mineralogical composition of an aggregate influences its adhesion with bitumen and therefore its dynamic modulus. However, few studies have been conducted on this aspect. One of the most used properties to describe the impact of aggregate on the adhesiveness phenomena is the zeta potential. In this study, the first mineralogical and chemical properties were considered through the percentage of silica in the rock source of aggregates and the electric aggregate particles charge zeta. Dynamic modulus values used for regression process are determined from complex modulus test on nine asphalt concretes mix designed with aggregate types (basalt of Diack, quartzite of Bakel and Limestone of Bandia). The results showed that aggregate with high percentage of silica have higher zeta potential than aggregate with low percentage of silica. The development of a zeta potential predictive model showed a strong sensitivity to silica. The results of the complex modulus tests showed that Hot Mixture Asphalt (HMA) mixed with aggregate containing high silica contents gave better results than those mixed with aggregates containing low percentage of silica. The dynamic modulus predictive models of HMA developed shows that it is the properties of bitumen that influence more. However, the effect of silica although low, is very marked at low temperatures and high frequencies.
