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Self Levelling, Mix Design & Compressive Strength
Make it self levelling driver!
 Words we here all too often. Like any producer we can only meet the requests and instructions of our customers. We are not builders or specifiers and cannot specify mix design. Needless to say advice is always available but, ultimately, the responsibility is on the client to order the correct mix. The basic fact is the wetter concrete is the easier it is to level. Unfortunately the desire to reduce the physical effort required to lay concrete often compromises its performance. Making the concrete 'too wet' normally manifests itself on performance concrete e.g. a driveway, with the concrete having a soft, dusty top layer leading to premature wearing. Requesting a very wet mix will also ultimately mean the job takes you longer if you want to achieve a floated finish.
Mix Design
Concrete and screed is produced to meet many applications, strengths and performance criteria. Each application will normally be covered by a common mix design providing the right strength and laying characteristics for the task at hand. Whilst the industry is covered by general standards unfortunately there is no single reference for concrete mixes. This makes it very difficult for customers to obtain comparable quotations ensuring the mix quoted by one producer is equal or better than that of another. Any producer can quote on cheaper mix designs to secure an order and it is virtually impossible for the customer to question the mix after supply. With our customers in mind we have endeavoured to simplify our own mix design ordering process, see mix designs.
Compressive Strength
 Testing of concrete follows set guidelines to determine and maintain the quality of the produced concrete. The strength of concrete is measured in terms of compressive strength that being a sample is crushed until point of failure and the level of force required to cause failures is registered. Results are taken at 7 / 14 and finally 28 days from concrete production with the 28 day strength being the stated strength of the concrete. It should always be remembered that strength tests are carried out under very specific site and laboratory conditions and, unless the concrete is handled correctly on site e.g. correctly protected and cured, the quoted strengths may not be achieved. |
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