What Factors Affect the Durability of Concrete?
Although concrete is one of the most durable materials used in the construction industry, there are occasions when it can start showing signs of wear and tear much earlier than expected. Madmix, who supply accredited concrete to businesses and households in Huntingdon, Royston, St Ives and around Cambridgeshire, identify some of the key factors that affect how concrete will last.
The Quality of Raw Materials
Concrete consists of a mixture of cement, aggregates and water. Cement is usually Portland cement, which is created from limestone. Aggregates include gravel, sand and stone. Water is the third and last key ingredient.
You need all of these to be of good quality for the concrete to be durable. For example, if the water is full of oils, acids, alkalis and other chemical impurities, the concrete won’t last as long as it should.
Ideally, aggregate particles should also be angular and round. If they are flaky and elongated, they could make the final mixture more porous and less workable – again, affecting the final mixture’s durability.
The Proportions of the Mixture
Even if all of the ingredients are of top quality, if they aren’t mixed in the right proportions, the quality and durability of the finished concrete will suffer. For instance, if there is too much water, although it will be more workable, it will also shrink too much when it dries, increasing the chance of cracking. On the other hand, if there’s too much cement, it won’t bond properly with the aggregate, again affecting strength and durability.
The Weather and Temperature
It is essential that concrete is not poured or laid in temperatures which are either too hot or too cold. If it’s too hot, then the concrete will dry out too quickly, making it more vulnerable to cracking, surface erosion and other forms of wear and tear, which will shorten its lifespan.
Even if the concrete has set, you still need to be careful because there is still moisture present, and the concrete needs to fully dry out in a controlled way (a process known as ‘curing’). For instance, if the concrete has been laid in winter, you may need to put some polythene sheets over it for up to 10 days (or seven days in summer).
There is also the freeze/thaw problem in more northern or colder climates. When water freezes, it expands, putting pressure on the concrete, which can rupture over time, particularly if the cycle repeats itself.
There is also the problem of rainfall and moisture. If concrete is being poured or laid during heavy rain, some of the cement in the concrete can be washed away. So if it has to be laid in such conditions, have tarpaulins and covers at the ready.
The Presence of Other Chemicals
A number of chemicals which aren’t naturally occurring can also affect the composition of the concrete and cause it to deteriorate before it should. This particularly applies to concrete used in storage facilities which house chemicals such as fertilisers, acids and any form of bio-waste.
Chlorides and sulphates (which can be present in water and soil can damage the cement in the concrete) as well as other reactive substances all pose a threat to the durability of the finished product.
Accredited Concrete in Huntingdon from Madmix
At Madmix, we supply accredited concrete to domestic and commercial customers from our base on the outskirts of Cambridge.
We have been given the BSI kitemark, which is only awarded to companies whose concrete meets the BS EN 206 and BS 8500-2 standards. This means it is guaranteed to be of high quality and not just in the ingredients used, but how it is mixed together.
We also supply a number of specific admixtures which get around some of the problems outlined above, such as waterproof concrete, which lets in less moisture. We also supply sulphate resistant concrete to our customers in Cambridge, Huntingdon, Royston and beyond, which is particularly useful for sewers, sewage works, water storage areas and bridges.
If you would like to know more about any of our admixtures, call us on 01954 212212 or click here for our full contact details and online contact form.
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