Implementation of NDT Techniques

Rebar location, layout, depth and clear cover determination

Though reinforced or prestressed concrete is very common in Bangladesh, there are cases when the Engineer needs to know the as-built information about the rebars. It is specially necessary to avoid risky rebar/ prestressing tendon hits during core cutting operation, assessing the safety of an existing structure or permitting for vertical or lateral extension, renovation works and in general the cases where reliable as-built drawings are not available. To this end, the Ferroscan PS 200 machine has been calibrated for local scenario and now being used extensively for different projects of BUET.

    NDT for estimating the compressive strength

    To determine the in-situ compressive strength of concretes, rebound hammers (Schmidt hammer) and Windsor pins (Resistance to Penetration Tests) are commonly used. However, the correlations between the rebound number, penetration value and the compressive strength depend strongly on the test condition and aggregate characteristics. To this end, we have developed the correlations in Bangladesh context so that the reliability in strength prediction can be enhanced.