Title:
Evaluation of Polymer-Modified, Cement-Based Mortars for Replacing Concrete Structures in Cold Climates
Author(s):
J. Mirza, R. Lapointe and M. S. Mirza
Publication:
Symposium Paper
Volume:
171
Issue:
Appears on pages(s):
367-388
Keywords:
Abrasion; bonding; cements; compressive strength; drying shrinkage;
erosion; freeze thaw durability; grout; mortars (material); permeability;
silica fume; thermal properties.
DOI:
10.14359/6106
Date:
8/1/1997
Abstract:
This paper describes the results of an ongoing test program to evaluate the performance of polymer-modified cement-based mortars for repairing surfaces up to a depth of 75 mm (3 inches) of concrete structures damaged due to exposure to cold climates. Twenty-five selected commercially available polymer-modified products, seven containing styrene butadiene rubber (SBR) and 18 containing acrylics were evaluated. They were compared with a pure cement-based mortar containing 8% silica fume with a water/(cement + silica fume) (W/C) ratio of 0.3 1. All of the mortars were subjected to physical and mechanical tests such as thermal compatibility with base concrete, drying shrinkage, permeability, abrasion-erosion resistance, bond strength, compresive strength and freezing and thawing. The thermal compatibility with the base concrete test at temperatures from -50°C to +5O°C was used as a preselection test. The test data indicated that the polymer-modified mortars, even from the same family, i.e. SBR or acrylics, showed mixed results, with their performance varying from one manufacturer’s product to another. This paper also presents the performance of the three best polymer-modified cement-based mortars (included in the 25 mortars), installed in 1992 on two spillways of a dam in a very severe environment. These mortars were exposed to the abrasive action of water-borne sediments as well as the stresses related to hydraulic pressure and rigorous freezing and thawing and drying/wetting cycles. The six inspections so far have found that these three products are still performing well after an exposure to very low temperatures for a period of four years.