Repair procedures for columns:

Surface Preparation: The lower sump (outlet sump and/or hopper bottom) area will be filled with approximately a foot of water to create a more humid environment, ideal for application and curing of repair mortars. The lack of sunlight and wind will also add to this ideal environment.

Contractor (LMC) will define the perimeters of the repair area, with approval by CM, ensuring adequate overlap. This area will be considered the "affected area." The affected area will be defined using ferroscan data to determine the height/point on the column that meets the 1 ½ inch minimum cover. Visual verification will be performed to determine the proper termination for the affected area. More verification may be achieved by the normal surface preparation and/termination processes. The waterblaster equipment will be utilized to remove concrete in an area sufficient enough to visually check the amount of cover. The hole created is expected to be 2" to 6" in diameter and only deep enough to see the steel. The hole will be repaired as explained later. No damage from hammers or other mechanical devices or abrasion of the reinforcing steel shall be allowed. Each affected area will extend 360 degrees around the circumference of the column and will be no smaller than four feet in height. If there are two or more affected areas on the same column there will be at least a three foot gap between them, or we will join/combine the affected areas. This is also true for the distance between the affected area and the slab/deck.

Hand removal of any large spatter, concrete debris etc.

"Affected Area" will be marked and identified in a manner such that waterblasting or sandblasting can be performed accurately. A strap impervious to the sand/waterblasting will be secured at the exact termination point prior to sand/waterblasting.

Waterblast of the entire affected area of concrete surface to achieve the ¼ inch amplitude (CSP5 or more) profile as recommended for bonding. Waterblasting will leave adequate profile for mechanical bond including exposing the large aggregate. This profile is demonstrated in the ICRI Technical Guide 03732 page 7, Selecting and Specifying Concrete Surface Preparation for Sealers, Coatings and Polymer Overlays. Concrete Surface Profile will be evaluated and approved during the mock-up process discussed later and approved by Master Builders and the CM prior to application of material.

Any honeycombed areas that may be discovered will be bushed to sound concrete with bushing hammers. (Hilti TE 55 or 15lb air bushing tools) Should the honeycombed area extend into the column's core as defined by the outside edge of the reinforcing spiral, the CM shall be notified at once to determine appropriate action. These areas are anticipated to be filled as part of the normal spray application process as defined below.

"Termination" points will require additional surface preparation to achieve edge detail per attachment. This will include a more aggressive waterblast operation. It may also be necessary to use small bushing/cutting tools (Hilti TE 55, 15lb air bushing tool, and small diamond blade cutting tool) to achieve the ½ inch amplitude (or ½ the thickness of the repair material to be applied) required at the termination. No special termination is required at the very bottom or very top of the column where the column interfaces the slab/deck except that the footing and/or drop panel shall be prepped the same as the surface of the column for the depth of the repair.

Concrete surfaces will be Saturated Surface Dry (SSD) prior to application of material. Truesdell Corporation will utilize LMC provided water delivered through hoses to an appropriate soaking device (perforated hose/pipe) for approximately 24 hours prior to application of material. This process will also remove any dust created by potential sandblasting or bushing. The water will be allowed to remain on the floor, adding humidity and assisting with application and cure. Any area that fails to absorb water will be re-prepped to acceptable standards. 9. A "scrub coat" consisting of a mix of Master Builders Emaco S88 (S88) will be machine delivered and scrubbed into the surface by hand as required for bond. This process will be completed just prior to machine application of the S88 material to avoid the drying/dusting of the scrub coat prior to spray application. Care will be taken to ensure that this process in no way prevents the column from receiving the required amount of repair material.