| Title |
High-Performance SB Latex-Modified Concrete for Ultra-Rapid
Hardening Concrete Bridge Deck Repair |
| Authors |
한형석(Han, Hyoungseok);정인우(Cheong, In Woo) |
| DOI |
https://doi.org/10.12652/Ksce.2025.45.3.0325 |
| Keywords |
Latex-modified concrete, Styrene-butadiene latex, N-methyl acrylamide, Ultra-rapid hardening concrete, Bridge deck repairs |
| Abstract |
The development of high-performance latex-modified concrete (LMC) for bridge deck maintenance requires a careful balance between
rapid strength gain, long-term durability, and environmental resilience. This study proposes an optimized eco-friendly styrene-butadiene
(SB) latex system tailored for ultra-rapid hardening concrete (URHC) applications. The concrete formulation incorporates elevated levels
of calcium (Ca2?) and aluminum (Al3?) ions to accelerate cement hydration, achieving an early compressive strength of 21 MPa within
4 hours?suitable for time-sensitive bridge deck repairs. To enhance colloidal stability and dispersion behavior of the latex in alkaline
environments, 2 wt.% N-methyl acrylamide and 1 wt.% acrylic acid were introduced through seeded emulsion polymerization. These
functional monomers improve hydrogen bonding and steric hindrance, contributing to uniform film formation and latex compatibility
in cementitious matrices. The butadiene/styrene ratio was adjusted to 40/60, resulting in a glass transition temperature (Tg) of
approximately 0°C. This adjustment enhances flexibility, impact resistance, and crack bridging ability. Furthermore, the average particle
size of the SB latex was reduced from 190 nm to 160 nm, significantly improving mechanical interlocking, flexural strength, and substrate
adhesion. The reduction in particle size also contributed to increased resistance against chloride ion penetration, a key factor in protecting
reinforcing steel. A high gel content exceeding 85 % was achieved, which effectively improved freeze-thaw durability and minimized
phase separation under cyclic environmental stresses. The synergistic effects of chemical structure, particle engineering, and hydration
control demonstrate that the proposed SB latex-enhanced URHC is a robust and sustainable solution for rapid bridge deck rehabilitation,
offering both immediate mechanical performance and extended service life under aggressive exposure conditions. These results highlight
the potential of the proposed latex system to strengthen infrastructure resilience and extend service life, while contributing to the
sustainability of bridge rehabilitation by enabling faster construction, reducing material waste, and improving long-term durability under
aggressive exposure conditions. |