论文部分内容阅读
为了探明固化期间缓黏结预应力混凝土梁的力学性能,制作了4根缓黏结预应力混凝土梁,每根梁直线布置3根缓黏结预应力钢筋,进行试验梁的抗弯承载力测试。通过邵氏硬度计测得试验梁缓黏结剂的硬度,用以反映缓凝材料在加载试验时的固化性质;然后把试验梁分4批进行三分点两点同步单调静力加载试验;最后通过监测梁挠度、关键截面混凝土的应变变化、预应力钢筋张拉端和锚固端的压力变化、裂缝分布等指标,明确缓黏结预应力钢筋与混凝土之间的传力机理以及混凝土梁的抗弯承载能力。结果表明:缓黏结剂的固化度对预应力混凝土梁的开裂荷载影响较小,对最大承载力影响较大,利用现有的预应力混凝土计算理论计算得到的开裂荷载与试验结果吻合较好,但最大承载力的理论计算结果相对保守;随着缓黏结剂逐渐固化,预应力混凝土梁的极限承载力随之增加,当缓黏结剂的邵氏硬度(D型)达到80时,缓黏结预应力钢筋与混凝土具有良好的共同工作状态,梁纯弯段部分的裂缝开展均匀,数量较多,其承载力及延性也最大。
In order to find out the mechanical properties of the slow-bonding prestressed concrete beams during curing, four slow-bonding prestressed concrete beams were made. Three beams of prestressed concrete with slow-bonding were arranged linearly on each beam to test the flexural capacity of the beams. The hardness of the slow beam binder measured by Shore hardness tester is used to reflect the curing properties of the retarded material during the loading test. The test beam is then subjected to three-point and two-point simultaneous monotonic static loading tests in four batches. Finally, By monitoring the deflection of girder, the change of strain of concrete with key cross-section, the pressure change of the tensile end and anchorage end of prestressed steel bar and the distribution of cracks, the mechanism of force transmission between prestressed steel bar and concrete and the flexural bearing capacity of concrete beam ability. The results show that the curing degree of slow binder has little effect on the cracking load of prestressed concrete beams and has a great influence on the maximum load capacity. The crack load calculated by the existing theoretical calculation of prestressed concrete agrees well with the test results, However, the theoretical calculation results of the maximum bearing capacity are relatively conservative. With the gradual curing of the slow binder, the ultimate bearing capacity of the prestressed concrete beam increases. When the Shore hardness (D type) of the binder is 80, Stress steel and concrete have a good common working condition, Liang Chun bending part of the crack to carry out a more uniform, the greater the number of its bearing capacity and ductility is also the largest.