Mechanical Behavior of Low-Strength Hydraulic Lime Concrete Reinforced with Flexible Fibers under Quasi-Static and Dynamic Conditions

Abstract

We investigate the effect of flexible fiber reinforcement on low-strength hydraulic lime concrete. This type of concrete is occasionally necessary to ensure compatibility with the substrate, particularly in the conservation and rehabilitation of historical heritage. For this purpose, we designed a matrix of hydraulic lime concrete based on a mix design method we proposed previously and added different amounts of polyvinyl alcohol fiber (volumetric contents of 0.3%, 0.6%, 0.9%, and 1.2%). We then conducted three-point bending tests on prismatic specimens with a central notch under quasi-static (displacement rate of 4 × 10−4 mm/s) and dynamic (4 mm/s) conditions, using a servo-hydraulic machine. The results indicate that, in both quasi-static and dynamic regimes, the flexural strength, the residual flexural strengths for different crack openings, and the work of fracture increase as the fiber content increases. Furthermore, transitioning from one regime to another (by increasing the strain rate or velocity) leads to a significant increase in these mechanical parameters.