Abstract
New types of artificial lightweight aggregates with high strength are recently available. Most of them are pelletized and coated lightweight aggregates made from finely ground minerals. Their water absorption is low due to their completely coated surfaces and the interior consisting of closed micro-cells. With application of these high-performance lightweight aggregates, structural concrete with high workability, high strength and high durability can be produced.
When this kind of concrete is used in reinforced concrete (RC) members, however, the shear carrying capacity decreases due to the increase in autogenous shrinkage and the decrease in fracture toughness. To clarify and to take advantage of combined effects of synthetic short fiber and shrinkage-reducing agent on improvement of shear carrying capacity, loading tests were performed using high-strength lightweight RC beams.
Since the conventional equation for evaluating shear carrying capacity recommended in JSCE Standard Specifications for Concrete Structures cannot be applied to structures using high-strength lightweight concrete, some practical method needs to be developed for the application of such concrete to structural members. The authors performed shear loading tests on RC beams to investigate their shear resisting mechanism and proposed a new evaluation equation for shear carrying capacity of high-strength lightweight RC beams with the effects of synthetic short fiber and shrinkage-reducing agent taken into account. The proposed equation was demonstrated to provide a good agreement with the experimental results.
