Exposed Aggregate Concrete in Cape Town

Exposed aggregate concrete in Cape Town: slab or topping

A poured slab has no sand joints. The City of Cape Town's Table 6-1, a guideline for carriageway crossings over the verge, gives 200 mm of in-situ concrete for medium- and heavy-duty crossings and lists no concrete option for a light-duty residential crossing. The table covers the crossing, not the driveway inside the property. Thin decorative toppings are a different product. Cemcrete's 8 mm Exposed Aggregate topping is not suitable for driveways or areas with vehicle traffic, and new concrete under it must be fully cured for 28 days first.

Exposed aggregate: the downsides

• Cracking. A US quick reference for concrete parking areas, based on ACI Committee 330 guidance, sets a maximum joint spacing, lays the joints out in square panels where practical, and recommends control joints at least one-fourth of the slab thickness deep. It applies unless local experience indicates otherwise.
• Curing time. The same parking-area reference keeps cars off new concrete for three days and trucks for seven, unless tests show it has gained adequate strength.

Exposed aggregate, paving or tar for one driveway

Exposed aggregate, driveway paving and tar surfacing are all quoted per job. A slab is divided by control joints. The CMA's construction manual, quoting SANS 1200 MJ, puts block paving joints at 2 mm to 6 mm, filled with sand. For pavers, see driveway paving in Cape Town. Paving for Africa lays all three, and its other services are on the paving contractors in Cape Town page.

Curing exposed aggregate concrete

Fresh concrete has to be cured. The parking-area quick reference says a liquid membrane-forming curing compound is usually recommended as the most cost-effective curing agent.

Exposed aggregate questions