DEVELOPMENT OF REINFORCEMENTS WITH HIGH-STRENGTH AND HIGH-DUCTILITY AND ITS APPLICATION TO STRUCTURAL MEMBER

以下是本研究的主要成果。确定了抗压强度≥1000kgf /cm^2的超高强混凝土配合比，并对材料的抗压强度、抗拉强度、杨氏模量等力学性能进行了详细研究。研制了屈服强度约为7000 kgf/cm^2、拉伸破坏时应变为15%的钢筋。对一种由超高强度混凝土和超高强度钢筋组成的钢筋混凝土梁进行了弯曲加载试验，研究了该梁在弯曲作用下的力学性能。以抗压强度为1200 kgf/cm^2的混凝土和屈服强度为7000 kgf/cm^2的钢筋为受拉钢筋，试验研究了无双配筋钢筋混凝土梁的抗剪性能，特别是抗剪动强度、荷载-位移关系以及应变和裂缝的发生状态。对这种双配筋钢筋混凝土梁的抗剪性能进行了试验研究。总结了以往类似试验的结果，研究了混凝土强度、受拉配筋率、有效高度、抗剪跨比等因素对引起斜裂缝的荷载、抗剪动强度等的影响，提出了适用于超高强度混凝土梁的实用设计公式。从断裂力学的角度考虑梁的抗剪性能，解析研究了这类RC梁的荷载-位移关系。在未来的研究中，将对超高强度混凝土与超高强度钢筋的粘结与锚固进行研究，同时对超高强度混凝土在循环荷载作用下的力学性能进行研究

The following are the principal achievements of the study.1.The mix proportions for super high strength concrete with compressive strength of 1,000kgf/cm^2 or more were established and the compressive strength, tensile strength, Young's modulus and other mechanical properties of the materials were investigated in detail.2.Steel reinforcement with a yield strength of about 7,000kgf/cm^2 and strain at tension failure time of 15% was developed.3.Bending loading testing of a reinforced concrete beam made of super high strength concrete and super high strength steel reinforcement was performed to study the mechanical properties of the beam under bending.4.Using concrete with compressive strength of 1,200kgf/cm^2 and steel reinforcement with yield strength of 7,000kgf/cm^2 as its tension reinforcement, the shear properties, particularly the shear dynamic strength, load-displacement relationship, and the state of the occurrence of strain and cracks of an RC beam without double reinforcement were experimentally studied. An experimental study of the shear properties of this kind of RC beam with double reinforcement was also done.5.Results of similar tests performed in the past were summarized and the effects on the load that causes diagonal cracks, the shear dynamic strength, etc.of factors such as the concrete strength, tension reinforcement ratio, effective height, shear span ratio, and others were studied in order to propose practical design formulae that can be applied to super high strength concrete beams.6.The shear behavior of beams was considered from the perspective of fracture mechanics to analytically study the load-displacement relationship of RC beams of this kind.7.In the future, studies of the bonding and anchoring of super high strength concrete with super high strength reinforcement will be done along with studies of the mechanical properties of super high strength concrete under cyclic loading