As you are probably aware, placing and finishing concrete in poor weather conditions can lead to defects in the hardened concrete. Defects can include, but are not limited to, plastic shrinkage cracking, accelerated setting and settlement cracking, dusting and crazing.
Burdetts are warning you of these potential problems, with the aim of working with you and your concreter, in an attempt to avoid or minimise any of these problems.
Please ensure you discuss this issue in detail with your concreter or finisher, and highlight to them the need for taking these extra precautions.
Do not add additional water to aid placement as it will reduce concrete strength and increase the potential for plastic shrinkage and drying cracking. Finishing aids should be used instead
The use of a quality crushed rock sub-grade MUST be dampened (with excess water removed) immediately prior to concrete placement, or PREFERABLY use a vapour barrier such as black poly. Dampen any side-forms.
Use shade or wind breaks to prevent the surface of the concrete from drying out.
Ensure concrete is placed with sufficient manpower in a timely manner.
Use of evaporation retarders, such as aliphatic alcohols, to reduce the rate of evaporation from the surface. www.allcongroup.com.au/Construction-Supplies/Curing/anti-evaporative
Keep fresh surfaces continually moist (I.e. Cured), commencing immediately the concrete has been finished. Methods may include ponding with water, use of wet hessian blankets, covering with plastic sheeting, or application of a commercial grade curing compound. www.allcongroup.com.au/curing-compound
Form or cut joints ASAP after finishing, ensuring any cuts are ¼ to 1/3 the depth of the pavement
Burdetts looks forward to working with our customers to provide the best quality finished product.
Good planning for placement and curing practices will ensure any problems are minimised or avoided. Far more detailed information and data sheets about these problems can be accessed from the Cement Concrete & Aggregates Australia website at www.ccaa.com.au