Investigation of Factors Affecting PCC Surface Resistivity through Ruggedness Testing

Abstract

Many entities currently use permeability specifications in Portland cement concrete (PCC) pavements and structures. Recent studies have shown surface resistivity testing correlates well with ASTM C1202 [“Standard Test Method for Electrical Indication of Concrete’s Ability to resist Chloride Ion Penetration,” Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2010] rapid chloride penetration (RCP) testing. The success of this research has led to surface resistivity testing on Portland cement concrete cylinders being implemented in Louisiana. However, many of the studies have questioned the impact of various factors on surface resistivity measurements. This project investigates a ruggedness factorial using many of the factors in question to determine the level of impact of each factor. A partial factorial consisting of 35 combinations of factors was developed using 11 factors and 16 mixtures. Some factors were mixture dependent; therefore, RCP testing was also performed on a portion of the factorial to determine if factors influence the surface resistivity meter or permeability in general. The ruggedness study showed age and aggregate type as significant factors for surface resistivity. Additional comparisons against a control suggested age, calcium nitrite, aggregate size, and aggregate type as significant factors for surface resistivity. However, comparative RCP testing on the same sample sets concluded that all significant factors determined either affect the permeability of the sample in general or will influence rapid chloride permeability as well.