concrete core sampling

Excel Building Surveying Ltd have recently been commissioned to complete core sampling at numerous sites from London, Bournemouth, York, Birmingham, Rustington, Edmonton, Edenbridge, Hayes and Brighton. The first included removing a number of core samples through new-build estate roads to confirm the Council`s specification for adoption had been met. Coring was completed using 110V hand-held hydrostatic diamond coring equipment powered by petrol generator. Core sampling proved the depth of concrete to be variable and in some positions inadequate for adoption. The second included core sampling a factory floor in Birmingham as part of a structural investigation into the slab`s capacity to accept increased loading from new machinery. Coring was completed using 110V bolt-down Shibuya coring equipment with 100mm diameter diamond coring barrels. The sampling was completed in association with in-situ slab strength testing using a bolt down goalpost steel frame and hydraulic ram to impose the proposed loads (+ a factor of safety) to prove the slab was competent. Further core sampling completed in Portsmouth was required to determine the slab thicknesses, concrete strength and underlying material. The sub-base was sampled using a hand auger and was shown to be contaminated with heavy oil thus necessitating re-design of the proposed structure. Further recent core sampling completed at Ilford and York were included as part of a wider structural investigation including half-cell testing, dust sampling, chemical analysis, electromagnetic scanning etc. Hydrostatic diamond core cutting requires a constant water supply to cool and lubricate the cutting head. This is usually controlled by cowl and wet-vac to minimise mess enabling coring to be satisfactorily undertaken within the majority of building types. In general, the main use of the concrete cores is for compressive strength testing which is completed in our partner UKAS laboratory however, following microscopic examination of a number of core samples, we have advised petrographic analysis of some cores to confirm the presence of delayed ettringite formation and alkali silica reaction.