United States Department of Transportation
i
Microsilica modified concrete for bridge deck overlays : second-year interim report.
-
1994-10-01
[PDF-970.86 KB]
Details:
-
Creators:
-
Corporate Creators:
-
Corporate Contributors:
-
Subject/TRT Terms:
-
Publication/ Report Number:
-
Resource Type:
-
Geographical Coverage:
-
Corporate Publisher:
-
Abstract:This report summarizes the performance of microsilica concrete (MC) overlays on seven distressed portland cement concrete bridge decks at three sites in Oregon. This report emphasizes the overlays' condition after two, or in some cases, three years of use.
After two or three years, there was cracking on all seven overlays and delamination on five overlays. On the two overlays without delaminations, the cracking had not increased during the second year of use. On the five overlays with delaminations, the number and length of the cracks and the number and size of the delaminations increased during the second and/or third year of use.
Despite the cracking, all of the overlays had no excessive surface wear or rutting, spalling around the crack edges, potholes, or popouts. No maintenance was required during the second, and in some cases the third year of overlay life except on one overlay where methacrylate and sand were used at a cost of $4,000. All of the overlays had adequate tire-to-pavement friction numbers.
The overlays met two of their three design objectives after two or three years' use. They were still adding strength to the deck and providing a smooth and durable wearing surface. However, as they were cracked, it is surmised that they are no longer sealing the underlying deck from the intrusion of chlorides.
The Oregon Department of Transportation is continuing to specify MC as an overlay material. Experience with the material and revision of the MC specifications has reduced construction problems, and consequently, improved the quality of the overlays.
It is recommended that the causes of the cracking on these overlays be investigated.
-
Format:
-
Collection(s):
-
Main Document Checksum:
-
Download URL:
-
File Type:
