Failure Analysis and Forensic Investigations
Concrete is a widely used precast element and used in-situ in walls, floors, foundations and structural components. There are rules in Eurocode 2 for use of concrete with regards to strength, durability, fire resistance and movement tolerances. When installations fail, a forensic examination is required to understand the failure mechanism in order to: detail methods of repair, understand the consequences of the failure, or ultimately, to be able to define culpability.
Lucideon has a number of techniques available for forensic/failure analysis which can be split into two categories; site investigation followed by laboratory analysis.
An initial desk study will be followed by a visual site inspection to assess the failure mode. Depending on the apparent failure, a programme of intrusive and non-intrusive sampling can be carried out:
Intrusive coring of samples to establish:
- Depth of cover to rebar
- Construction of slab/column/beam
- Presence of honeycombing
- Moisture content and density
- Depth of foundation.
- Mapping of rebars using Hilti Ferroscan
- Presence of voids using Ground Penetrating Radar (GPR)
- Estimated compressive strength using Schmidt Hammer or Windsor Pin
- Presence of movement joints
- Drop hammer testing of screeds to establish strength
- Slip/skid testing of surface
- Half cell potential.
- Compressive strength*
- Mix proportions including identification of additives*
- Petrographic analysis*
- Sulphate content*
- Chloride content*
- Depth of carbonation
- Alkali silica reaction
- Presence of High Alumina Cement (HAC)*
Lucideon is a UKAS accredited test laboratory for many tests to BS 1881 and BS EN 12390, including the ones marked with an *.