| A cold substrate will cause an increase in the viscosity of the injection resin. This slows down the rate of injection. A hot substrate results in premature jelling of the resin with sequential loss of penetration. During extremely hot weather an open bridge deck may exceed temperatures as high as 140 Degrees F. Special precautions are necessary before injection work can be done in such weather.
The precaution may be shading the bridge, and water cooling. Always check substrate temperature. The injection machine and its hoses require isolation from extremes of temperature.
Epoxy injection undertaken during cold weather also requires special precautions.
When doing injection work in freezing conditions, determining if there is ice present in the crack is critical. Determining if a cracks inner surfaces are ice coated, is equally important. When injecting under these conditions, the resin will not bond to the substrate and no structural rebonding will result. It is usually safer to preheat the portion of the structure you are injecting.
When heating a structure do not overheat it. This closes the crack. When removing heat, the crack may rapidly open. This will rupture the resin before it has a chance to achieve final cure. In most cases, indirect heating is much more desirable than direct heating. Maintain heat for several hours before and after the injection application. |
