Delamination's in concrete slabs are one of the critical issues. They can be heard much before they can be visualized. Delamination's can be identified when you get to hear a drummy sound or loud clack rather than the clear ringing sound when the metal hits robust concrete.
If you will use the hammer to tap around this spot you will identify more hollow-sounding areas. This can be termed as surface delamination in the concrete floor.
Looking upon the severity of the issues there are many delamination-identification concrete testing services to identify delamination in concrete structures.
This guide will shed light on the concept of delamination in concrete and the testing procedures for concrete delamination.
What are the Major Causes Behind Delamination?
In the process of laying fresh concrete, the solids such as cement and aggregate tend to settle down. This settlement which is quite natural leads to excess mixed water and entrapped air to be displaced. Further, the lightweight materials drift towards the surface.
In case the finishing operations start off prematurely and the surface is closed or sealed prior to the completion of bleeding, then air and/or water are trapped under the densified surface mortar. Gradually when the concrete gets harder then subsurface voids get developed where the water or air is trapped. Due to these voids, there are weakened zones beneath the surface that can detach during slab use.
So the thin mortar layers over delamination's might even detach when they are struck with a hammer when you try to sound out the extent of the delaminated area.
What are the Testing Procedures for Concrete Delamination?
There are many specialized evaluations and construction activities opted to identify and remove delaminated areas of concrete. One of the most common methods is “sounding” which refers to the application of a consistent, repetitive, percussive force applied to the concrete surface with the motive of producing a series of impact sounds and audible responses from which a skilled operator can deduce and delimit the presence and extent of slab delamination.
Generally, there are three Procedures Covered in this Practice Which are Mentioned Below:
Procedure A, Electro-Mechanical Sounding Device
Under this procedure there is the use of an electric-powered tapping device, sonic receiver, and recorder mounted on a cart. The cart is pushed to the deck of the bridge and delamination's are recorded on the recorder.
Procedure B, Chain Drag
In this procedure a chain is dragged over the bridge deck surface. The investigation of the delamination's is done by the operator who notes down dull or hollow sounds. Instead of using a steel rod or hammer, a chain drag is a good alternative.
Procedure C, Rotary Percussion 2
This process incorporates rolling a dual-wheel, multi-toothed apparatus that is attached to an extension pole over the bridge deck surface. Due to the percussive force caused by the tapping wheels, there is a dull or hollow sound which indicates delamination.
The testing procedures for indicating delamination have made it facilitating and convenient to identify and work upon the concrete issues beforehand. Concrete Insight is a platform conducting concrete delamination testing in VA, in accordance with the Standard Practice for Measuring Delamination in Concrete Bridge Decks by Sounding. So make sure you count on this platform for effective and reliable delamination testing.