01373569

Component

Clay lumps and other friable materials that are embedded in pavements, bridges, tunnels, and other concrete structures have presented a problematic issue for many decades. Unfortunately, there has been little help from the area of non destructive testing (NDT) concerning the location of clay lumps below the surface of the concrete. This paper describes the use of a low-frequency ultrasonic inspection system that successfully detects the presence of clay lumps at two of three levels of interest in pavement slabs: above the reinforcement layer, at the reinforcement layer, and below the reinforcement layer. Six specimens were constructed with known contaminations of measured lumps at these varying depths, and the results of the scanning procedure were compared with the documented construction key. Lumps found at the reinforcement layer are shown to be vaguely discernible, which is a result of reflective interference from the steel, while lumps found everywhere else in the volume were easily detected. This preliminary study in detecting deleterious substances will allow lump populations to be assessed in construction applications via non-destructive techniques, furthering quality control in pavements, bridges, tunnels, and other concrete structures.

This paper was sponsored by TRB committee AFN20 Properties of Concrete

01362476

12-3822

English

13p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; Photos; References (12) ; Tables

Concrete pavements; Concrete structures; Contaminants; Nondestructive tests; Quality control; Reinforced concrete pavements; Slabs; Ultrasonic tests

Highways; Materials; Pavements; I32: Concrete

Transportation Research Board Annual Meeting 2012 Paper #12-3822

TRIS, TRB

Feb 8 2012 5:19PM