The abrasives used under each machine were produced by the individual equipment manufacturers and designed for optimal performance based on the characteristics of the machine. Each abrasive used refined the concrete to the maximum potential before moving to the next. Refinement of each grit went beyond simply replacing the scratch patterns from the previous grit. You know when you have refined the concrete with each grit to its maximum potential when the slurry becomes translucent and there is no visible scratch pattern to the naked eye. Maximum refinement is critical when reaching for a floor that will have a crisp, clean appearance with maximum clarity of overhead reflection; it is also as import to the floor's durability.

The densifier on this project was from RetroPlate. Application of a densifier is based on the absorbency of your project's concrete; on this job we typically applied the densifier after our 100-grit resin pass. To continue with the floor protection plan started before the polishing began, once my team completed each area of the floor the general contractor laid down a temporary floor protection system to protect the finished surface.

One of our primary challenges on this job was grinding to expose aggregate then honing and polishing the edges flush to the existing finished block. This was done with a combination of stand-up edge machines and four finishers on rolling carts using various shapes and sizes of abrasives and hand tools. The ground floor was built slab-on-grade and the joints were filled with VersaFlex SL 75 polyurea.

Another considerable challenge was handling the excessive amounts of slurry produced from the deep grinding operation. During the first half of the job slurry was pumped into a lined dumpster with sump pumps. This became costly, messy and ultimately counterproductive when the hoses started to freeze due to winter working temperatures. The solution came in the way of a water/slurry separator that allowed reuse of the filtered water and easy disposal of ground concrete patty cakes. The cakes were disposed of in the trash dumpster along with all other construction debris.

When completed, we left the school with a maintenance plan that addressed the use of entrance matting, vacuuming loose dry debris with backpack vacuums, mopping with micro fiber pads, the use of Diamond Bright Polished Concrete Cleaner (a slightly alkaline cleaner) and burnishing the floors with a polished concrete maintenance pad.

With the efforts of all parties involved the finished floor exceeded the owner's expectations.

Project at a Glance

Owner: Wicomico County Board of Education

Architect: Becker Morgan Group, Inc.

General Contractor: Whiting-Turner Contracting Company

Flooring Subcontractor: Harkins Concrete Construction

Polishing Subcontractor: Cuviello Concrete

Key products and equipment:
RetroPlate densifier; ProGuard Dura Cover; Substrate Technology's Prep/Master 4430; Superabrasive's Lavina 32 Pro; VersaFlex SL 75 polyurea; Adhesive Systems Technology Corp. application unit; finisher carts from RACATAC Products; GOLZ Slurry Fox water/slurry separator from Substrate Technology Inc.; L.M. Scofield integral color; Heritage Glass.