Landscape Specification

CONTENTS

Hot Weather Placing
When surrounding outdoor shade temperature exceeds 38°C, do not place concrete. To prevent premature
stiffening of the fresh mix and reduce water absorption and evaporation losses utilise protection methods to
prevent the rapid loss and evaporation of free mixing water from the concrete. Be sure to mix, transport,
place and compact the concrete as rapidly as possible.

Before and during placing maintain the formwork and reinforcement at 32°C using protection, cold water
spraying, or other effective means. When placed in the forms, the temperature of the concrete must not
exceed 35˚C for normal concrete in footings, beams, columns, walls and slabs and 27°C for concrete in large
mass concrete sections; or concrete of strength 40MPa or greater, in sections exceeding 600 mm in
thickness.

Select one or more of the following methods of maintaining the specified temperature of the placed concrete:

•   Use chilled mixing water.
•   Spray the coarse aggregate using cold water.
•   Cover the container in which the concrete is transported to the forms.
•   Cool the concrete using liquid nitrogen injection before placing.
•   A combination of these methods

Curing and Protecting Concrete
Take responsibility for the curing and protection of the concrete. For example: protect freshly cast concrete
from premature drying and excessively hot or cold temperatures. Erect windbreaks to shield the concrete
surface during and after placing. Maintain the concrete at a reasonably constant temperature with minimum
moisture loss for the curing period, refer AS 3600.

Cure as soon as the surface of the concrete has hardened sufficiently to prevent damage but in no case later
than two hours after the finishing operation has been completed.

Cure by the following means:

•    The use of waterproof paper, or
•    The use of an approved polyethylene building film.
•    The use of other approved moisture retaining covering.

If a method other than polyethylene film is adopted, secure the covering material against the concrete for the
full length of edges and laps and at frequent intervals between so that no air circulation at the concrete
surfaces occurs.

Continue final curing for seven days for normal Portland cement concrete. For high early strength concrete,
continue the final curing for three days. Prevent rapid drying out at the end of the curing period. Keep wet
steel forms heated by the sun and wood forms in contact with the concrete during the final curing period.

When the mean temperature of the air during curing is less than 5°C, maintain the temperature of the
concrete between 10°C and 20°C for the required curing period.

When the mean temperature of the air is in excess of 30°C during curing and moist curing is not employed,
cover the surface with an approved heat reflecting plastic membrane. Apply this treatment for the whole of
the curing period.

Take special care with curing off-form concrete to avoid differences in colour. Curing compounds shall
comply with AS 3799. Produce uniform colour on adjacent surfaces.

Remove debris and form work from each area after stripping concrete as work sections are completed.
Leave each area clean to the satisfaction of the Superintendent.

Jointing
Periods of stoppage in concrete of 3/4 hour or more are deemed to be construction joints.




URBIS
URB-SPC-LAN-P0025138                                                                                     PAGE   18