Test methods for the evaluation of the durability of covercrete.

摘要

Fluid ingress plays an important role in most deterioration mechanisms and the surface cover provides the initial resistance to such factors as de-icer salt penetration, freeze-thaw resistance, and sulphate attack. Surface durability testing must evaluate resistance to the predominant mechanism of initial fluid ingress: capillary absorption or sorptivity.;The primary focus of this study was to develop a non-destructive test device suitable for field use to evaluate the potential durability of covercrete by determining the rate of absorption of concrete. This type of testing device must be simple to use, easily handled in the field, portable, and inexpensive. The particular device developed in this research allows for ease of operation and accommodates a wide range of applications such as vertical, horizontal or sloped surfaces, and smooth or rough finishes; while providing consistent, meaningful results in a short period of time. The development of this apparatus was based on principles presented in the British ISAT Test BS 1881, Part 5: 1970; since it focuses on rate of water absorption, the most important mechanism associated with early fluid ingress. Tests of this nature, however, are very sensitive to moisture content of the surface concrete, as it will drastically alter the rate of absorption. Consequently, suitable corrections for a range of moisture contents are incorporated for the in-situ usage of the surface absorption device.;In this contribution, the development of the field rate of absorption equipment is described and both laboratory calibration, and field data are presented.