High performance composite structures with combination of expansive concrete and fiber reinforcements

为了研究高性能复合材料结构的抗弯性能，进行了高强膨胀混凝土与纤维增强材料的组合试验。增强纤维分为短纤维和连续纤维。钢筋混凝土构件深度限制在10cm以内。膨胀混凝土的目标抗压强度大于80N/mm^2。高强膨胀混凝土可以应用于组合钢结构中，既可以保护钢的腐蚀，又可以利用膨胀混凝土较高的膨胀能有效地引入化学预应力。钢构件与高强纤维增强膨胀混凝土的突出结合可获得高性能的组合结构。根据研究结果，提出了一种高性能复合材料结构的设计方法。1)高强度膨胀混凝土中加入更多的短碳纤维或短乙烯基纤维。膨胀混凝土抗压强度大于80N/mm^2。选择合适的组合后，不仅要进行混凝土的配合比设计，还要考虑高性能膨胀剂的掺量和短纤维的掺量。2)当混凝土板与钢梁之间的粘结强度足够强时，化学预应变沿组合钢梁高度呈线性分布。但在梁的边缘存在粘结强度较差的情况下，化学预应变在高度方向上不能得到线性分布。这种现象在较高的组合钢梁结构中更为明显。3)钢梁上部位置的纵向化学预应变受影响较大，但远离钢梁位置的化学预应变略大，因为钢梁的约束较弱。4)当混凝土与钢梁之间的粘结强度足够强时，可获得较高的组合钢梁抗弯性能。因此，化学预应力混凝土的效果取决于粘结强度的牢固性和程度。5)膨胀混凝土的径向做功与单轴A法约束几乎相同，即使内钢管厚度与外钢管厚度相差5倍左右。少

In this study, in order to experimentally investigate the flexural behaviors of high performance composite structures, trial combinations of high strength expansive concrete and fiber reinforcements were carried out. Fiber reinforcements consist of short fibers and continuous fiber reinforcements. A depth of reinforced concrete member is limited to 10 cm. Target compressive strength of expansive concrete is larger than 80N/mm^2. High strength expansive concrete can be applied to composite steel structures for the purpose of not only to protect steel corrosion but also to introduce chemical prestress effectively by using higher expansive energy of the expansive concrete.High performance composite structures can be attained by the prominent combination of steel members and high strength fiber reinforced expansive concrete. From the research results, a design method of high performance composite structures is proposed and following items are gained.1)High strength expansive concrete with … More short carbon fibers or short vinyl fibers can be manufactured. Compressive strength of the expansive concrete is larger than 80N/mm^2.after selecting appropriate combinations of not only mix design of concrete but also quantity of high performance expansive additive and content of short fibers.2)Chemical prestrains are lineally distributed across the height of composite steel girders if bond strength between a concrete slab and a steel girder is strong more than enough. However linear distributions of chemical prestrain could not be gained for the height direction if the poor bond strength is existed around a edge of the girder. The phenomena can be seen easily for the higher composite steel girders.3)Though longitudinal chemical prestrains at the upper position of the steel girder are strongly affected, chemical prestrains are a little larger at the position far from the steel girder due to weaker restraint by the steel girder.4)Higher flexural behaviors of the composite steel girder can be attained if the bond strength between concrete and steel girder were strong enough. Therefore the effect of chemically prestressed concrete depends on the soundness and degree of the bond strength.5)Radial directional work-done by the expansive concrete is almost the same as that of uni-axial A method restraint even if the thickness of inner steel pipe and of outer steel pipe are varied about five times. Less