Investigation of premature distress around joints in PCC pavements
Abstract
Some of the Indiana concrete pavements that have been constructed within the last 10 years have shown signs of premature deterioration, especially in the areas adjacent to the longitudinal joints. This deterioration typically manifests itself as cracking and spalling of concrete combined with the loss of joint sealant. These processes create a cavity in the joint area that traps water and, as a consequence, accelerates further deterioration of concrete during the freezing and thawing cycles. The objective of this study was to examine in details the microstructural and chemical changes in concrete extracted form the affected areas in an attempt to determine the cause of this premature deterioration. The investigation started with a detailed inventory of selected areas of affected pavements in order to identify and classify the existing types of distresses and select locations for collection of the cores. The cores have been collected from the following four locations: NB lines of I-65 near downtown Indianapolis, SR 933 near South Bend, Intersection of 86th Street and Payne Rd. in Indianapolis and a ramp from US67 to I-465E, also in Indianapolis. A total of thirty six 6-in. diameter cores were removed from pavements at these locations and transported to the laboratory where they were subjected to eighth different tests: air-void system determination, Scanning Electronic Microscopy (SEM) analysis, X-ray diffraction (XRD) analysis, sorptivity test, freeze-thaw & resonance frequency test, resistance to chloride ion penetration (RCP) test and chloride profile (concentration) determination. The test results identified several cases of in-filling of the air voids (especially smaller air bubbles) with secondary deposits. These deposits were most likely the result of the repetitive saturation of air voids with water and substantially reduced the effectiveness of the air voids system with respect to providing an adequate level of freeze-thaw protection. In addition, the affected concrete often developed an extensive network of microcracks, showed higher rates of absorption and reduced ability to resist chloride ions penetration.
Degree
M.S.C.E.
Advisors
Olek, Purdue University.
Subject Area
Civil engineering
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.