Surface preparation is essential
Properly cleaning and preparing surfaces before applying concrete crack repair materials is crucial to the efficiency of your repair and long-term success. Many surface preparation methods are available, including detergent scrubbing and acid etching.
Some abrasive techniques may leave a thin layer of dust on the surface. This should be removed with a high-pressure water blast. A shot blast is often used to remove contaminants and create rough surfaces. This can be done with ICRI CSP 3 or ICRI CSP 3. It is important to remove any concrete laitance, surface contaminants, and traces or release oils and curing substances using some abrasive.
Pressure washing is an option. 5000 psi is the recommended pressure for concrete surfaces. It is strongly recommended that cementitious surfaces are not overworked, or water used excessively. This will ensure the best possible performance of the repair. ACI 503R and ASTM 4263 are applicable specifications.
Elcometer tab pulls
Unexpected issues can cause surface bonding problems even with the best preparation and a small mockup. You can quickly test the bond between any coating or repair material in suspected areas for a very small investment by using small circular metal tabs. ASTM D4541 explains the entire process. This test is performed using an Elcometer 106 portable pull-tester. This test is known for having reproducibility issues, so make sure you have plenty of dollies to help with your evaluation. A home-built version can be made using 2″ diameter pipe caps (ground flat), and an Enerpac(r). If you choose this option, a third party should check the calibration.
Create a mock-up
Preconstruction shows that you are prepared to go the extra mile to ensure a high-quality project. This is particularly useful if you plan to use a different material. Ensure that there are no disagreements about the appearance of the material before you start the project. Sometimes you may be compensated for your materials and time.
Get $ off local aggregates
Many manufacturers pack their polymer mortars or grouts in 3-package systems. This includes pails or bags of graded sands.
Shipping a dense, low-cost product like sand across the country or abroad can be very expensive. We don’t believe it is necessary. If you have a need for this type system, please call us and we will make recommendations to local suppliers. This can save you significant time and money for both you and your customer. In polymer mixtures, only dry sand should be used (less than 0.2% moisture).
Estimate using a margin for waste
Most repair jobs that use epoxies or other polymeric products (not counting coatings), the material cost ranges between 5-10% of total job costs. This includes other materials and equipment as well as labour. There may be negative consequences if you underestimate and your men run out of time.
The first is that the guys may reduce the application rate, which could affect the performance of areas that were already short. They might also call you late Friday afternoon to request a very expensive delivery by air. Or, your crew might be required to remobilize as the owner might need the area in service while they wait for the replacement material. You don’t have to pay a lot of money to buy epoxies. They are long-lasting materials that can be used on future projects, or you can return them in their original condition for a 15% fee.
You will likely save a lot on labour if you buy more material. If your guys find that there is a little more work than they originally thought, you can request a change order.
