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South Dakota Department of Transportation
Project Synopsis
SD1992-03


Title: Evaluation of Silicone Joint Sealant Performance
Project Researcher: Arial Soriano,
Project Manager:
Research Period: -
Status:
Cost: $0.00

Problem Statement:Sioux Falls area has reported widespread incidents of silicone joint sealant failure concentrated on urban sections of concrete pavements. A preliminary survey done in August, 1991 revealed adhesion failure rates of from 10% to total failure on urban pavements sealed between 1984 and 1990. Highway sections in the vicinity sealed with silicone sealant within the same time frame experienced a much lower degree of failure. Potential contributing factors for these failures could be:
  1. timing of sealant placement

  2. traffic damage to uncured sealant

  3. drainage

  4. joint design and construction

  5. freeze-thaw cycling and deicing chemicals

  6. aggregates

  7. sealant.

A combination of several of these factors is suspected to cause these dramatic failures.

There is a definite need to know how widespread these failures really are and whether our current PCC joint sealant policies are adequate. It is also extremely important to determine if there is some fundamental flaw in silicone joint sealants.

Findings:

Research Objectives:
1  To identify the mechanism of adhesion failure of silicone joint sealants in Sioux Falls
2  To determine whether the problem can be corrected by modifying materials, specifications or procedures and recommend appropriate changes which will assure acceptable sealant performance
3  To compare cost effectiveness of silicone and alternate joint sealants based on the study results

Research Tasks:
1  Select appropriate urban and rural projects to provide information on the performance history of silicone joint sealants.
2  Conduct a survey of these projects statewide to determine the extent of silicone sealant adhesion failures and any potential causes.
3  Compare projects with good performance to those with varying degrees of failure to determine the significance of the possible factors contributing to the failures.
4  Identify laboratories capable of conducting failure analysis and submit samples of both failed and satisfactory performing cores of in situ silicone joint sealant in concrete to one of them for analysis.
5  Establish test sections by resealing failed joints in Sioux Falls following recommended procedures and opening them to traffic at various times (0-3 days).
6  Install test sections on new construction in Sioux Falls with varying concrete curing times (1-7 days).
7  Review the performance of existing hot pour joint sealant in Sioux Falls for comparative purposes.
8  Monitor performance of sealants for five years.
9  Analyze results and recommend appropriate changes in construction practices, specifications or materials.
10  Submit a final report describing the research methodology, findings, conclusions and recommendations.
11  Present the results of the research and any recommendations to the Research Review Board.

Documents Available:
SD1992_03_Final_Report.pdf

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