1. Influence of freeze–thaw cycles on properties of asphalt-modified epoxy repair materials
Construction and Building Materials
蔡季洋
2014/03/17

2. Introduction
Concrete, the multiphase heterogeneous brittle material, presents low tensile strength and bad toughness.
Cracks decreased service life, especially the durability of concrete structures.
In the arcticalpine and highland areas of China, such as low temperature, big differences in temperature, drying and watering cycle, freeze–thaw cycle, salt alkaline corrode, and wind erosion.
Several repair materials, such as epoxy resins, polyester resins, polymer latexes, and polyvinyl acetates, are used for repairing cracking concrete structures.

3. Introduction
EP coatings in industry ,poor impact resistance and cracking resistance.
Modify epoxy resin by introducing various reinforcing and toughening agents and fillers, such as rubbers and asphalt.
The influence law of the asphalt content on the properties and structure of the epoxy repair materials suffered freeze–thaw cycle and chemicals is investigated through using interior freeze–thaw circulating experiment

4. Materials and methods Preparation of the epoxy repair materials
Procedure of the freeze–thaw circles(immerged into the tap water in plastic bottles)
0, 10, 20, 30 phr
into the epoxy resin
stiring 30 min
resin/asphalt mixture was reduced to room temperature
Asphalt 120℃
15 phr of curing
agent was added into the blend
At room
temperature for
2 weeks
14 h in the freezer(-20)
4 h deicing in 100% relative humidity chamber(50 ℃)
6 h in the oven
for drying.(50 ℃)
1 CYCLE

5. Results and discussion
-OH
2925, CH3, CH2
835,1510,1035
p-phenylene groups
1035
aliphatic carbon–oxygen
910
epoxy groups
FTIR spectra of asphalt-modified epoxy resin before (a) and after cured (b).

6. Influence of asphalt content on mechanical property of epoxy repair materials
56.6 Mpa
5.9Mpa
Effect of asphalt content on tensile shear strength and compressive strength.

7. Influence of asphalt content on mechanical property of epoxy repair materials
SEM micrographs of the epoxy repair materials without (a and b) and with (c and d) asphalt modification: (a) and (c) 600X, (b) and (d) 2000X

8. Effect of freeze–thaw cycles on compressive strength and water resistance of epoxy repair materials
Compressive strength upon different freeze–thaw circles.
Weight decrease ratio upon different freeze–thaw circles.

9. FTIR spectra of asphalt-modified epoxy resin before (a) and after freeze–thaw circles (b).
The asphalt-modified epoxy material has been cured much more completely

10. The chemical resistance of repair materials after freeze–thaw circles was investigated with 10 wt% of H2SO4, 10 wt% of NaOH, and 10 wt% of NaCl at the temperature of 80 ℃ for 2 weeks.
10 wt% of H2SO4
2 wt% ↓
10 wt% of NaOH
2 wt% ↓
10 wt% of NaCl
2 wt% ↓

11. Conclusions
A kind of asphalt-modified epoxy repair materials with excellent freeze–thaw resistance is developed in this research.
10 phr of asphalt has the outstanding mechanical property, and the compressive strength and tensile shear strength can reach 56.6 MPa and 5.9 Mpa.
The mechanical property further increases upon the freeze–thaw circles.
The weight change ratio of all samples is below 1 wt% upon 30 freeze–thaw circles and chemicals soakage.
These results can provide theoretical basis and practice for further optimizing the repair materials and the application in the arcticalpine and drought environments.

12. The end

13. 两种高聚物相容性差，共混后形成非均 相体系，分散 相分散在连续相中，像 小岛分散在海洋中一样，称为海岛结构 。