Why Exposed Aggregate Driveways Are Harder to Clean in Arizona
Exposed aggregate concrete driveways have a decorative textured surface created by removing the cement paste layer to reveal the aggregate (gravel, stone, or pebble) embedded in the concrete matrix. This textured surface is visually appealing but significantly harder to clean than smooth concrete — the gaps between aggregate pieces trap dust, staining, and biological growth that a simple pressure washing rinse doesn't reach.
In Arizona's environment, the challenges compound. Desert dust and silica particles settle into every gap in the aggregate texture. Hard water irrigation overspray deposits mineral scale on the aggregate surface and in the gaps. After monsoon rain, mud dries into the textured voids. The result is a driveway that looks progressively dingy even with regular garden hose rinsing.
Professional Exposed Aggregate Cleaning Method
Effective exposed aggregate driveway cleaning in Arizona uses a rotary surface cleaner attachment — a spinning head that provides even pressure distribution across the textured surface at 2,500–3,000 PSI. The spinning jets reach into the aggregate gaps that a standard wand nozzle passes over. Hot water at 160–180°F increases cleaning effectiveness for organic staining and oil deposits.
A degreaser pre-treatment applied to oil-stained areas and a mineral treatment for hard water scale areas before the power washing cycle improves results on both common Arizona contamination types. The post-wash rinse uses a clean water pass to flush loosened debris completely from the aggregate voids.
Should You Seal Exposed Aggregate Driveways in Arizona?
Sealing exposed aggregate driveways in Arizona with penetrating concrete sealer is strongly recommended. Penetrating sealer fills the pore structure of the concrete matrix between aggregate pieces — reducing the rate at which desert dust, mineral deposits, and oil absorb into the surface. The aggregate itself remains exposed and textured; the sealer penetrates below the surface without adding a surface film.
Sealed exposed aggregate driveways are measurably easier to maintain than unsealed surfaces — the next cleaning cycle requires less time and chemistry when contamination can't penetrate as deeply. Arizona's intense UV also breaks down unsealed concrete faster, causing surface dusting and aggregate loosening over time.