We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal ...We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal with the interfacial transition zone（ITZ） and make it stronger is the key point for this concept. Considering that silane coupling agent（SCA） can provide a better bond on a silicon-containing material surface, it was introduced as a modifying material to further improve the bond quality of the ITZ between lightweight aggregate and cement paste. Results indicated that the water absorptivity of lightweight aggregate can be controlled by SCA solutions, and the pull-off bond strength, mechanical strength, and microhardness were increased, which was attributed to the optimized microstructure under the condition of an appropriate concentration of SCA.展开更多
Microscopic techniques were employed to investigate element enrichment characteristics in the vicinity of the interracial transition zone （[TZ） of MgO concrete. Results indicated that the morphology of products of h...Microscopic techniques were employed to investigate element enrichment characteristics in the vicinity of the interracial transition zone （[TZ） of MgO concrete. Results indicated that the morphology of products of hydration in 1TZ was similar to the cement matrix but different by amount, size and crystal features. Elements Ca, Si, AI and Mg were obviously enriched in ITZ and uniformity of their distribution grew with age. MgO was non- uniformly distributed in concrete, accounting for 8.47% and 4.53% respectively in paste and ITZ area despite of fully mixture in construction, yet MgO showed inclination of migrating towards ITZ area with in-depth hydration and the gap in between was mit- igated from 3.94% at 7 d to 1.31% at 240 d so far as 5% of light- burnt MgO was incorporated.展开更多
基金Funded by the National Natural Science Foundation of China(No.51172173)
文摘We experimentally studied the fine lightweight aggregate with the particle size range of 3.15-4.75 mm used as functional bridge between FRP sheet and concrete substrate. However, problems would appear and how to deal with the interfacial transition zone（ITZ） and make it stronger is the key point for this concept. Considering that silane coupling agent（SCA） can provide a better bond on a silicon-containing material surface, it was introduced as a modifying material to further improve the bond quality of the ITZ between lightweight aggregate and cement paste. Results indicated that the water absorptivity of lightweight aggregate can be controlled by SCA solutions, and the pull-off bond strength, mechanical strength, and microhardness were increased, which was attributed to the optimized microstructure under the condition of an appropriate concentration of SCA.
基金Supported by the Twelfth Five-year Science and Technology Support Program (2011BAE27B01)the National Natural Science Foundation of China(51139001, 51209022)China Central Non-profit Research Funds for Institutes (CKSF2012035/CL)
文摘Microscopic techniques were employed to investigate element enrichment characteristics in the vicinity of the interracial transition zone （[TZ） of MgO concrete. Results indicated that the morphology of products of hydration in 1TZ was similar to the cement matrix but different by amount, size and crystal features. Elements Ca, Si, AI and Mg were obviously enriched in ITZ and uniformity of their distribution grew with age. MgO was non- uniformly distributed in concrete, accounting for 8.47% and 4.53% respectively in paste and ITZ area despite of fully mixture in construction, yet MgO showed inclination of migrating towards ITZ area with in-depth hydration and the gap in between was mit- igated from 3.94% at 7 d to 1.31% at 240 d so far as 5% of light- burnt MgO was incorporated.
