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- Penetration Resistance Tests on High Strength ConcretePublication . Lopes, Sérgio Manuel Rodrigues; Nepomuceno, MiguelThe aim of the investigation described here is to verify the applicability of penetration resistance tests on high strength concrete as a way of estimating its compressive strength “in situ”. A relationship between compressive strength of a given concrete and its resistance to penetration by a steel probe fired into the concrete surface is presented to a compressive strength range varying from 50 MPa to 90 MPa using an alternative firing apparatus to the standard apparatus Windsor Probe Test System.
- A Comparative Study of Penetration Resistance Apparatus on ConcretePublication . Lopes, Sérgio Manuel Rodrigues; Nepomuceno, MiguelThe existence of a relationship between the compressive strength of a given concrete and its resistance to penetration by a steel probe fired into the concrete is well known; the depth of penetration will be inversely proportional to the compressive strength. A test apparatus, designed for this purpose, using a special probe and standardised powder charge, was developed in the USA during the 1960s’ and is known as Windsor Probe Test and covered by the ASTM Standards (ASTM-C803-90). In Europe, similar standards are the British Standards (BS 1881: Part 207: 1992). The aim of this work is to perform studies concerning to a new apparatus application in comparison with the WPT System, which was called Alternative Firing Apparatus (AFA). Five different mix proportions were produced in order to obtain five sets of specimens with five different classes of compressive strength. The tests with the two described systems were performed at 28 days age for each set of specimens. The obtained results show that the Alternative Firing Apparatus could be a suitable mean for the assessment of in-place strength. The main physical limitation of penetration resistance tests is the surface damage and the danger of splitting of members, which limits the zones of testing. However, it was found that the Alternative Firing Apparatus causes less damage than WPT System. Consequently, minor distances between probes are possible.