... these can be affected by the conditions under which it is made and placed. I also intend to discuss the use of alternative materials within concrete, and how this can solve important waste disposal issues. A Historical Note Concrete in some form has been around for many thousands of years, and types of cementing material have changed. Ancient Egyptians used calcined impure gypsum, whilst the Greeks and the Romans originally used calcined limestone, but later learned to add sand and crushed stone or brick and broken tiles to lime and water. This was the first concrete in history. Throughout the Middle Ages, the use of cement in construction declined, and it was only in the 18th century that people began to advance the quality and knowledge of cement and concrete. Health and Safety There are many different health and safety aspects to be taken into account when working with concrete. First and foremost is the ...

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