Research Projects

Appropriate design and use of high-strength concrete (HSC) with compression strength above 60MPa is beneficial in durability and material volume reduction in construction projects. Recent advancements in concrete technology have made HSC popular in building construction. However, the performance of HSC relative to normal-strength concrete is not well understood, especially regarding the influence of HSC on shear resistance in RC members. Therefore, designers have been cautious when extending the empirical shear design equations for members with HSC. To facilitate the broader applicability of HSC in India more efficiently, it is imperative that suitable guidelines be formulated. This project aims to add knowledge on this front by studying the cyclic performance of squat shear walls built with HSC and proposing suitable guidelines for analytical modelling and designing these critical members. To make the large-scale use of HSC economically viable, a delicate balance between structural function and material cost with HSC must be achieved. Using HSC in shear members is significant in this context as the component capacity is pseudo-linearly associated with concrete strength. By contrast, the rebar yield strength largely controls the strength of flexure dominant members. Thus, the increase in strength with HSC (and associated economic and performance benefits) may be more pronounced in shear members. More importantly, shear failures are brittle, causing additional concern for HSC adoption without reinforcement reduction. To address this, an experimental and analytical study is proposed to examine the behaviour of shear dominant members such as squat reinforced concrete walls with high-strength concrete under quasi-static loading. A comprehensive experimental program consisting of cyclic loading of RC squat walls built with HSC is proposed in this project. Squat walls are chosen for their shear-dominant behaviour and expected brittle failure. A total of 16 specimens are considered under this program. These tests aim to observe the failure of these members with parametric variations such as axial load ratio, wall aspect ratio, thickness, concrete grades, boundary longitudinal reinforcement ratios, web reinforcement ratios, spacing of transverse reinforcement, etc. The experimental results will provide valuable insight into the behaviour of HSC under shear, leading to diagonal tension or diagonal compression failures. Crack formation and propagation in planar shear will be studied to derive analytical models for application in shear capacity and shear deformation estimations of members built with HSC. The findings are expected to advance the development of robust shear strength and deformation models of components using HSC members. The performance will be benchmarked with existing analytical models used for normal-strength concrete, providing a quantitative advantage of using HSC over NSC, thereby promoting the adoption of HSC in construction.