Concrete basics for building: Storage of materials

Even the best quality materials can deteriorate if stored incorrectly. Follow these guidelines to make sure that you get the most out of the money you have spent.

 

1. Cement

For short periods, cement can be stored out of doors on a platform raised above the ground and covered with plastic sheeting to keep it dry.

If you are ordering more than 10 bags of cement at any one time, you will need a storage area or shed that is watertight and as airtight as possible. Provide a dampproof barrier such as a plastic sheet or wooden platform on the floor, and stack the bags away from the walls, not more than 12 high. Use the cement as soon as possible, preferably within two or three months.

For larger projects, there are obvious advantages in having the cement either:

• Delivered to the site in weather-proof silos by the producer, or
• Delivered on shrink-wrapped pallets

Lumps in cement indicate that the bag has been exposed to moisture.

• If these lumps can be broken easily by hand, use the cement but add a little extra cement to each batch of concrete.
• If the lumps are hard, sieve them out, increase the cement content of the mix by 10-15% and use the concrete only for unimportant work.

2. Aggregates

Before stone and sand is delivered, identify a storage area close enough to access roads to allow tipper trucks in and out, but also as close as possible to where the concrete will be mixed. Clear all grass, rubble, etc. from the ground.

If possible provide a concrete floor slab, laid with a fall to facilitate drainage.

When the aggregates arrive on site, control tipping to prevent segregation and intermingling. If more than one stone size or different sands are to be used, make sure that they are separated physically and provide clearly legible labels on stakes for each type.

It may be necessary, where wind-blown dust or sand could contaminate the material, to provide some form of shelter or protection for the aggregates.

Source: Cement & Concrete Institute. Photograph: Cantilever Racks.