Concrete road slabs must be reinstated with C32/40 concrete mixed in accordance with MCHW Clause 1001 and using an air entrainment admixture in the top 40 mm (at least) of the road slab. Exceptionally, where agreed, a concrete road slab may be reinstated with an alternative material to suit site conditions, e.g. a high early strength mix may be agreed to allow an earlier re-opening of a heavily trafficked road.
Where concrete is mixed off site, Quality Assurance certificates detailing the specifications against which the concrete has been ordered and supplied must be obtained by the undertaker for confirmation of material quality. Where possible, the concrete should be obtained from a plant that holds a Quality Assurance certificate.
Information on the slab type and its condition, joint spacing and the presence of any other features near the proposed excavation should be requested from the authority by the undertaker. If this information is not made available, then an inspection survey commissioned by agreement may be carried out.
All expansion, contraction and warping joints removed or damaged during excavation must be replaced or reconstructed to a similar design, using equivalent materials at the time of permanent reinstatement.
The cured road slab may be opened to traffic as soon as a compressive strength of 25 N/mm² has been achieved. The compressive strength may be measured on samples cured under conditions representative of the site conditions.