Using NDT methods for evaluating the cementitious material after repair according to ACI 224 procedure

Abstract

According to American Concrete Institute, formation of cracks in concrete components can have different reasons; and effects show themselves just superficially, or noticeable they decrease in durability or/and instability of components. Materials and methods of repairing cracks are of different types and have been chosen after analyzing the crack according to ACI224.1R-07 report along with issues mentioned in ACI546.3R-06 report titled as “Concrete Repair Guide". After repairing the crack in concrete, there are different ways to control quality of usable materials, but most of the approaches related to filling cracks are among destructive tests and are impossible in some cases. After surveying causes of crack formation, approaches and needed materials to repair by information have been brought in ASTM C 597 standard, and in respect to differences of pulse velocity in environment with different densities, quality of repaired mortar and comparison of it with a normal concrete in this paper will be discussed. In the trend of experiments, an internal free space has been made in a mortar, especially a internal free space has been filled with the purpose of increasing load capacity through common methods mentioned in ACI224.1R-07 (Resin Epoxy Injection, Grout Injection, Routing and Sealing). Finally through comparison of pulse velocity in controlled mortar with required concrete and results from nondestructive ultrasonic test, the filled areas of cracks have been determined through a nondestructive method.