Application of the rebound test for the technological control of concrete hollow-core slabs

Abstract

Hollow-core slabs are precast elements produced with very dry concrete, which hinders the molding of cube or cylindrical specimens normally used for the technological control of the material. This paper addresses the use of the rebound test for the technological control of concrete applied to hollow-core slabs. An experimental program divided into two phases was developed. In the first phase, three concrete mixtures were produced and compressive and rebound tests were performed in cylindrical and prismatic specimens for 6 hours to 28 days for the obtaining of a correlation curve. In the second phase, a hollow-core slab was built with one of the concrete mixtures used and the same tests were applied. The results showed the rebound number correlates well with the compressive strength, which confirms the possible application of the test for the technological control of the concrete used in the construction of hollow-core slabs.

Flexural and direct tensile strength ratio for concrete unusual cross-sections

“…The studies addressed are limited and report results only for rectangular cross-sections. On the other hand, structural elements with unusual cross-sections have been largely used in several precast concrete industries due to their versatility, production speed, durability, and safety [19]. Besides, such studies usually disregard the influence of strength and aggregate type of the concrete, which are important factors in tensile behavior [20], [21].…”