摘要: |
One of the growing number of preventive bridge maintenance activities conducted by the Kentucky Transportation Cabinet (KYTC) is washing and applying thin film protective coatings to bridge abutments and piers. Previous work conducted by Kentucky Transportation Center (KTC) under KYSPR 10-406 documented increased chloride contamination of these bridge components and the need for protective coatings. KYTC Contract ID 162952 includes, among other tasks, cleaning and coating specific concrete elements of eighteen bridges in Anderson and Woodford counties (District 7). These elements are interior faces of the barrier walls, pier caps, and abutment seats. The contract was let on July 29, 2016, with the primary completion date as July 31, 2017. There were five bids that ranged from $326,870.61 to $810,645.00 with the engineering estimate as $475,155.08. The contract was awarded to the low bidder, M&M Services Co. Inc., on August 5, 2016. For most of the project the contractor had two crews — a pressure washing crew, consisting of two foremen and six workers, and a painting crew with one foremen and six applicators. Various crew members changed at times due to other commitments of the contractor. Of the coating systems identified in KYSPR 12-433 and KYSPR 05-291 the contractor selected the PPG Amerlock 2/Devoe Devflex HP system. Most of the systems were identified by laboratory testing with limited field application. This study focused on monitoring and documenting surface preparation, coating application, and field performance to determine the potential for use on future projects and possible inclusion of the coating on a List of Approved Materials for Concrete Coatings. Six of the eighteen bridges in this contract were monitored, and critical elements in the overall process were assessed and documented. This included initial substrate condition, surface preparation, application method, applied film conditions (e.g., thickness, continuity), and weather conditions. The bridges selected for monitoring were: (1) Continuous Span – B00027N and B00019N; (2) Simple Span – B00026N and B00037N; and (3) Steel Multi Span – B00007L and B00007R. |