LABORATORY TESTING OF PORTLAND CEMENT CONCRETE PATCH MATERIAL, MODIFIED TO REDUCE OR ELIMINATE SHRINKAGE
This study was initiated in response to the development of early distresses in the patch material of a dowel bar retrofit (DBR) project located in Marshfield, Wisconsin. Primarily, the slightly modified Minnesota Department of Transportation (Mn/DOT) 3U18 patch material used on the Wisconsin Department of Transportation (WisDOT) DBR project exhibited microcracking and debonding from the sidewalls of the DBR slots. These distresses are a result of shrinkage. Since the Mn/DOT 3U18 patch material is significantly less expensive than other proprietary rapid setting patch materials and its components are readily available, WisDOT deemed it worthwhile to seek an inexpensive way to improve the performance of the material. Three main concepts were identified as possible techniques for reducing shrinkage in the Mn/DOT 3U18 patch material: expansive cements or additives, shrinkage reducing admixtures, and internal curing through the use of saturated lightweight fine aggregate. The 11 products used to modify the Mn/DOT 3U18 patch material in this study were Type K cement, Komponent, Denka CSA #20 (50.56 lb/cu yd or 30 kg/cu m), Denka CSA #20 (42.14 lb/cu yd or 25 kg/cu m), Denka CSA 100R (50.56 lb/cu yd or 30 kg/cu m), Denka CSA 100R (42.14 lb/cu yd or 25 kg/cu m), Peramin SRA330, Eclipse Plus, Tetraguard AS20, Solite, and Hydrocure. Sealtight 2255-White, a poly-alphamethylstyrene-based concrete curing compound, was also evaluated for its effectiveness in preventing water loss from the surface of the patch material in comparison with Sealtight 1600-White, a water-based, wax-based curing compound. After extensive laboratory testing, it was found that only the Denka CSA #20 product, at a 50.56 lb/cu yd (30 kg/cu m) dosage rate, and the Tetraguard AS20 were able to successfully reduce shrinkage in the Mn/DOT 3U18 patch material without negatively impacting other vital properties required for concrete patch materials. Patch material containing Denka CSA #20 is approximately 10% less expensive than patch material containing Tetraguard AS20, but both products provide significant cost savings when compared to some proprietary rapid setting patch materials. It was also found that the Sealtight 2255-White showed 69% less water loss than the Sealtight 1600-White, but is also three times more expensive than the Sealtight 1600-White. Both curing compounds, however, met WisDOT specifications for both water retention and reflectance.
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Corporate Authors:
Wisconsin Department of Transportation
Bureau of Highway Construction, 3502 Kinsman Boulevard
Madison, WI United States 53704 -
Authors:
- Bischoff, D
- Toepel, A
- Publication Date: 2004-7
Language
- English
Media Info
- Features: Appendices; Figures; Photos; References; Tables;
- Pagination: 87 p.
Subject/Index Terms
- TRT Terms: Admixtures; Cost effectiveness; Curing agents; Expansive cement; Laboratory tests; Patching mortar; Portland cement concrete; Retrofitting; Shrinkage
- Uncontrolled Terms: Internal curing; Rapid setting patch materials; Shrinkage reducing admixtures
- Subject Areas: Highways; Materials; I32: Concrete;
Filing Info
- Accession Number: 00977174
- Record Type: Publication
- Report/Paper Numbers: WI-01-04,, Final Report
- Files: TRIS, STATEDOT
- Created Date: Aug 19 2004 12:00AM