Polymers for latex modified concrete
Bridge deck deterioration is a major problem wherever de-icing salts are used. De-icing salts are a major contributor to corrosion of the rebar within the bridge deck. The breakdown begins when salts attack the deck surface. Water carries oxygen and chloride ions through the pores in the concrete to the surface of the steel. An oxidation process creates pressure, causing the concrete to crack. The cycle of cold winter freezes followed by mild temperatures opens the concrete even further. Eventually the bridge deck crumbles.
Conventional concrete system challenges
- Moisture, weather cycles, and heavy traffic loads encourage voids and cracks to form
- De-icing salts penetrate the voids and cracks and corrode the rebar
- As rust forms around the rebar, pressure around the reinforcement increases
Role of latex in concrete
Addition of latex to conventional unmodified concrete reduces the amount of water required to achieve the appropriate viscosity for placement of the mix. This lower water requirement results in a cured concrete with higher compressive strength. The latex forms elastic membranes throughout the matrix of concrete, reducing the formation of voids and hairline cracks during the curing stage. The Latex Modified Concrete (LMC) resists penetration of oil, water, salts and aids in the adhesionof new concrete to old. The flexural strength is improved, and there is increased abrasion resistance.