Portland Cement Concrete Pavement Joint Sealant Practices and Performance (2021)

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3   Introduction In recent decades, Portland cement concrete (PCC) pavement joint sealing material tech- nology has continued to evolve, as have joint sealing practices (Shober 1996). Some of this evolution has occurred with respect to sealant configuration, design, preparation, and espe- cially the use of narrower joints; however, in some instances it seems to run counter to long-established recommendations. There also appear to be significant nonuniformity and inconsistency in joint sealant selection for a given set of project conditions. Even though joint sealing practices have long been established, the effect of the deviation from current recom- mended practices has not been well documented. Furthermore, questions exist as to the efficacy of joint sealants, and a need exists for the establishment of a standardized approach to joint sealant selection as well as for tools to assess the effect of sealant performance on a given PCC pavement (PCCP) design. Synthesis Objectives The objective of this synthesis is to document current practices with PCC pavement joint sealant in new construction and in maintenance protocols for existing joint sealants used in PCC pavement construction. The study is intended to showcase examples of practice, lessons learned, specifications, and performance effectiveness associated with the use of joint sealants in concrete pavement construction. Synthesis Scope and Approach Information gathered includes the following: • Whether PCC pavement joint sealants are used • Types of materials used for PCC pavement joint sealants • Construction methods used for PCC pavement joint sealants • Use of National Transportation Product Evaluation Program (NTPEP) data for product approval • Inspection and/or acceptance procedures and specifications used for PCC pavement joint sealants • Long-term PCC joint sealant performance • Issues surrounding PCC joint sealant usage or effectiveness, such as the presence or movement of water and noise contributions • Alternative methods being used in lieu of sealing joints (e.g., penetrating sealers) in an attempt to better control the saturation level of the joint face, including their specifications, performance, and installation procedures C H A P T E R 1

4 Portland Cement Concrete Pavement Joint Sealant Practices and Performance Information for this report was collected through a literature review, a survey of state agencies, and follow-up discussions with selected agencies for the development of case examples documenting existing practices. Information gaps and suggestions for research to address those gaps are also identified. Organization of This Synthesis Chapter 1 – Introduction This chapter includes background information and identifies the issues to be addressed as outlined in the scope of the synthesis. It also lists the synthesis objectives as identified by the Topic Panel and describes the final scope for the synthesis. It concludes with a description of the report organization and summarizes specific items that are included in each chapter. The rest of this synthesis is organized as follows. Chapter 2 – Literature Review Chapter 2 reviews the literature and summarizes joint sealant practices and, to the extent possible, sealant performance for new and reconstructed concrete pavements. Results of the literature review were used, where appropriate, to refine questions included in the agency questionnaire described in the report. Chapter 3 – State of the Practice This chapter addresses the development of the questionnaire and summarizes the results regarding agency joint sealant practices, specifications, and procedures. The questionnaire was configured to identify agencies that indicated use of and experience with joint sealing and that could be contacted for follow-up inquiries to obtain additional information relevant to the synthesis. The questionnaire was issued in the form of an online survey for direct input from participating agencies. The questionnaire had 42 responses (84 percent) out of 50 states. Considerable effort was expended to obtain information related to joint sealant specifications and long-term joint sealant performance: agencies were contacted to improve the survey response rate, and the target list of departments of transportation (DOTs) for follow-up interviews was expanded. Despite these efforts, little was forthcoming with respect to long-term performance data. Most agencies recognize the importance of joint sealing and have maintenance policies that are accordingly aligned with that perspective. It appears, however, that many agencies do not monitor joint sealant performance in ways that allow them to ascertain a change in sealant condition relative to how it may affect pavement performance. Much of the information on joint sealant practices was extracted from agency-submitted documents (e.g., specifications, manuals, policies, and reports). This information included the following: • Design of the joint sealant – Joint sealant shape factor – Minimum initial reservoir width – Surface configuration for joint sealing • Joint preparation – Cleaning procedures – Moisture preparation – Joint preparation inspection – Initial installation practice

Introduction 5   • Performance – Performance life – Factors affecting performance – Distress type • Maintenance (resealing) – Resealing criteria – Resealing method • Alternate methods Chapter 3 also summarizes the results (Appendix A) from the questionnaire in graphs and tables that present a view of the state of the practice and performance of joint sealing in the United States. Chapter 4 – Case Examples This chapter addresses case examples of joint sealing practices on specific projects from several state DOTs. The information collected explains practices used on these projects. Chapter 5 – Conclusions The synthesis concludes with a summary of the overall findings from the survey and the case examples. This information was used to identify areas for future research, which are also presented in this chapter.