Title: Substrate Absorption and Its Influence on Plastic Shrinkage of Repair Material

Author(s): K. C. G. Ong, W. Xu, and P. Paramasivam

Publication: Symposium Paper

Volume: 193

Issue:

Appears on pages(s): 337-352

Keywords: absorption; expansion; plastic; repair; shrinkage; surface

DOI: 10.14359/5831

Date: 8/1/2000

Abstract:
The moisture condition of the substrate surface prior to repair influences the plastic shrinkage and resultant physical properties of the repair material after repair. Absorption of moisture by the substrate may cause not only plastic shrinkage of the repair material adjacent to the interface, but also expansion at the surface to be repaired due to uptake of moisture and may lead to the premature debonding of the repair material. In this investigation, substrate prisms of four different thicknesses (30, 48, 66 and 1OOmm) under three different moisture condition (oven dry, natural dry and saturated surface dry) were employed to investigate the absorption and expansion of the substrate when it is immersed in water or comes into contact with the freshly cast repair material. Based on the test results obtained, a suitable pre-wetting time before repair work is begun is proposed.