Compressive strength and density of concrete

Compressive strength and density of concrete

In order to investigate the physical properties of hardened concrete in a structural element, cores can be taken for subsequent laboratory testing and/or examination.

Commonly this will involve an examination of the core to record properties such as aggregate type, degree of compaction, cracking and presence of reinforcement, subsequent to the determination of its density and compressive strength.  The equivalent cube strength, an estimation of the compressive strength of the concrete when originally cast, can be determined from the compressive strength by calculation.

Cores of various diameter and lengths can be tested. However it should be noted that testing standards state that a core diameter of less than three times the nominal aggregate size may provide adversely low results.  A minimum prepared length/diameter ratio of 1.0 is also recommended.

Ideally cores taken would avoid reinforcing steel that may be present in the parent concrete, although corrections can be made for such id steel is present.

Subsequent to any trimming that may be necessary, cores will be capped with a sulfur compound prior to testing.

Cores may be tested for both density and compressive strength in either an as received or saturated state.

Findings of the examination, density and compressive strength testing are presented in a tabular form.

The density of a concrete core is determined in accordance with BS EN 12390-7:2009; the compressive strength in accordance with BS EN 12390-1:2012 and BS EN 12504-1:2009, all testing being covered by our *UKAS accreditation.