Tensile Cracking and Bond Behaviors of Reinforced Lightweight Concrete

• Main Authors: Hsin-Lun Wu, 吳欣倫
• Other Authors: How-Ji Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/84334918275009371759

碩士 === 國立中興大學 === 土木工程學系所 === 100 === The specification for cracking the deflection of reinforced concrete beam （RC）calculations, have to consider the tension stiffening effect of concrete, but are assuming no slip between the steel and concrete. Therefore, in order to accurately predict the cracking of the RC beam deflection, we need to study the bond stress-slip behavior between adjacent cracks.And the damage situation of the bond of lightweight aggregate concrete（LWAC） and normal weight concrete（NWAC）are different, so this study by the local bond stress-slip test and tensile test of reinforced lightweight concretetension cracking and bond behavior, and compare the use of LWAC and NWAC, the two differences in characteristics between the bond. The parameters of local bond stress-slip tests include three concrete strength（20 MPa, 40 MPa, 60 MPa）, three kinds of steel bar size（#4, #6 and #8）and three coarse aggregate（normal weight aggregate, reservoir sludge lightweight aggregate（Type A）and waterworks sludge lightweight aggregate（Type B））. The results of bond stress-slip relationship curve to explore the impact of these various parameters for the performance of the bond between steel and concrete, and the establishment of various parameters of the local bond stress-slip equation. The test results show that when the concrete compressive strength increased, the ultimate bond strength to increase as a result. If the slub height and the diameter ratio（h/db）of the bar is larger, the ultimate bond stress is the greater. In the conditions of the same size of the bar, the ultimate bond stress of low strength LWAC specimen is slightly lower than the low strength NWAC specimen, and the ultimate bond stress of high strength LWAC specimen is significantly greater than the high strength NWAC specimen. In the same compressive strength of concrete, if the performance of the coarse aggregate is similar, the ultimate bond stress are also close. In addition, the steel stress distribution, the steel strain distribution, the concrete stress distribution, the concrete strain distribution, the bond stress distribution and the slip distribution between adjacent cracks which can know by reinforced internal adhesive strain gauges of double pull-out test and the theoretical derivation. The results show that the bond stress-slip relationship differ with position. By local bond stress-slip test to obtain the local bond stress-slip relationship, and then determine a function of position, the product of the two can express the bond stress-slip relationship in different location. A local bond stress-slip of the equation and the location of function to import RC flexural beam analysis model, and by the cross-sectional analysis and the derivation of the theoretical mechanics can predict the cracking of the central deflection of the RC beam in each load.