Important Slab Note:

A common misconception is that any standard slab can achieve a premium mirror reflection. Inexperienced operators promise high-end finishes without realizing concrete must be poured to strict trade specifications. Premium polishing relies entirely on uniform stone distribution and high cement paste density. Local mix problems—like poor aggregate grading, the use of soft limestone cement, unwashed sands, or even crusher dust can cause the surface chemistry to fail.

Forcing a high-end finish on these poor mixes is a complete waste of time and money. If a pour is unpredictable, skip the gamble and choose a Commercial Grind & Seal or a Honed Indoor Finish.

New Slabs – Mandatory Mix Design & Pre-Pour Specs

• Cement Type (CRITICAL): Strictly Type GP (General Purpose) cement only. To achieve a high-quality polished finish, cement replacement in concrete is typically limited to 20% for Fly Ash (Type GB), 30% for Slag (GGBFS), and 10%–12% for Limestone (Type GL). Exceeding these amounts can lead to issues like soft, chalky paste and poor visual results.
• Compressive Strength: Minimum 32 MPa structural mix (40 MPa highly recommended for premium zero-stone or nil-exposure finishes). Soft, standard 20–25 MPa driveway mixes will crumble under heavy planetary grinding.
• Zero Crusher Dust: The mix must use clean, washed sharp sands. Crusher dust destroys the cement paste density, absorbs excessive water, and leaves a dead, dusty, micro-pitted surface that cannot take a crisp, high-gloss mechanical polish.

• Surface Flatness: Finished to a strict Class A / Class 1 flatness tolerance using a mechanical power trowel (helicopter). Rolling foundations or deep trowel ridges destroy aggregate consistency during grinding.
• Slump & Water Control: Maximum 80mm slump at the truck discharge point. Absolutely no site water is to be added to the mixer by the pump crew. Diluted cement paste causes aggregate segregation (sinking the stone to the bottom mesh) and leaves a weak, dusty “cream” surface layer that won’t hold a mechanical edge.
• Chemical Controls: Controlled water-reducers only. Strictly no heavy overdosing of superplasticisers or fluidisers to force an “easy” self-levelling pour. Overdosing separates the mix and leaves a gummy, rubbery surface laitance that instantly melts and clogs premium diamond tooling.
•  Curing & Processing Windows: Slabs using standard Type GP cement must cure for 28 days minimum before grinding. If the plant accidentally supplies a limestone blend, the processing timeline must be extended to 45+ days to account for slower early strength.
• Local DIY Supplies Warning: Do not apply any curing products, chemical compounds, or retail sealers without asking ProSand first. The truth is, the local DIY supply shops do not know what they are selling when it comes to mechanical polishing preparation. Off-the-shelf retail products create permanent barriers that completely block the liquid densifiers and chemical hardeners we must inject during our polishing stages—effectively ruining our entire refinement process.