> For the complete documentation index, see [llms.txt](https://alchemco.gitbook.io/alchemco-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alchemco.gitbook.io/alchemco-documentation/surface-preparation.md). # Surface Preparation Surface preparation is critical in allowing ETT to perform as designed. The following should be considered when preparing the surface for application. ## Goal The goal when preparing the surface for ETT should be clean, sound, and absorptive concrete. ETT requires absorption as it is designed to take shape in the capillary/pore network within the concrete. The surface at the time of application should readily absorb water. One way to test the absorption of the concrete is to pour a small quantity of water onto the surface and visually assess its absorption properties. If water remains pooled on the surface for an extended period of time, then the surface will likely require further treatment. The surface must be dry to the touch at the time of application. If the surface is dry but slight isolated damp areas can be visually seen, that is okay – absorption is the key factor. Removal of absorption hindrances There are many things that contribute to absorption being limited. These items should be removed prior to achieve the absorption needed for ETT to function properly. Existing coatings, remnants of previous coatings, painted areas, line stripings exceeding 4”, oil stains, densifying concrete surface finishes, chemical curing compounds, and silane/siloxane water repellents shall be removed prior as these will hinder absorption and result in ETT being unable to penetrate into the concrete. Failure to remove these may affect warranty coverage. We highly recommend utilizing the cleaners found within our ACRtec product line. *(see Supporting Systems – Accessory Items)* ## Cleaning requirements The following are mandatory for all applications. Failure to comply with cleaning requirements may affect warranty eligibility. We require the use of either pressure washing or shot blasting when preparing the surface for ETT, depending on the surface profile/condition. Shot blasting is required in cases where previous coatings or contaminants need to be removed, or a new surface profile must be achieved. Other means of mechanical abrasion are also permitted so long as the resulting substrate meets absorption and profile criteria outlined in this guide. In cases where shot blasting is unnecessary, pressure washing may be utilized to clean the surface. Final cleaning must be performed using high-compression jet air (and a vacuum if needed) to remove residual cement dust and debris that would otherwise cause ETT to have a surface level reaction rather than absorb. {% embed url="" %} ## Structural Repairs & Removal of Unsuitable Concrete/Patch Materials ***Structural issues that become apparent after water/load/stress testing are the responsibility of the general contractor or relevant party and are required to be remediated prior to any ETT application.*** All surfaces must be free of patching materials, coatings, or repair products that may inhibit absorption or are incompatible with ETT. Additionally, all defects, voids, and discontinuities shall be treated in accordance with this guide. If preparation in the manners outlined in this guide is not possible, additional detail work utilizing products from our ACRtec and/or enDuratite lines may be required to refrain from warranty exclusions. For further clarification/additional guidance, please contact Alchemco’s Technical Department. ### Previous Patches / Repair Materials Most commercially available patch and repair materials contain polymers that are pore-blocking and are incompatible with ETT. Polymer-modified patches, sealants, or dense repair mortars shall be removed during preparation and replaced after application to maintain continuity of ETT systems within the substrate. ### Honeycombs / Honeycombing Honeycombed areas shall be mechanically opened to expose surface level voids and remove unsound material. This must be done prior to ETT application to maintain continuity within the substrate and ensure proper absorption. ### Tie Rods The holes left after removing the tie rods used during framework should be left open for the ETT application. Afterwards, they may be filled in using enDuratite Repair Grout or another approved Alchemco cementitious product. *(see Supporting Systems – Accessory Items)* ### Spalls / Delaminated Concrete Areas of spalled or delaminated concrete shall be mechanically removed to expose a sound substrate prior to ETT application and only repaired after application is complete. Please utilize the 1 or 2 finger rule. ### Active Leaks (If Present) In the event of an active leak prior to application, the leak must be chased back to the origin as much as possible to relieve pressure and allow it to drain. If the leak does not fully drain, enDuratite Plug may be utilized to quickly stop the leak. Once the leak has been stopped, apply ETT into the remaining cavity and fill using enDuratite Repair Grout. After the cavity has been repaired, apply one more coat of ETT and coat the repaired area with enDuratite Mlastic extending at least 4 inches in all directions surrounding the repaired leak. Please apply products in accordance with their respective TDS’s and contact the Alchemco Technical Department for further guidance. *(see Supporting Systems – Accessory Items)* ### Exposed Reinforcement / Corrosion Where reinforcement is exposed, ACRtec Rust Converter & Inhibitor shall be utilized during preparation to reduce the potential for future corrosion before ETT application and repairs that follow. *(see Supporting Systems – Accessory Items)* ### Inadequate concrete cover – Hammer Test Where there is incorrect placement of reinforcement that results in inadequate concrete cover, a hammer test is preferred in the immediate and surrounding areas. A hammer test is also preferrable for voids and cavities. A hammer test is a great tool that will expose unsound concrete and will assist in achieving a watertight structure.