Concrete Aggregates - Sand
Beach sand
Much as the name sounds beach sand is often just that. Unwashed and ungraded sand with foreign organic material is not suitable for concrete mixes and would severely compromise the quality of the finished concrete.
Play sand
Locating the correct type of sand for making concrete can be difficult to a beginner and many people will end up using “play sand” which is sold as a sterilized and tumbled sand product. The fact that the sand is sterilized is not a problem, in fact this would be preferable for all concrete mixes.
The tumbling process is specifically done to remove any sharp or rough edges to the sand. While ideal for a sandbox this negatively impacts the quality and strength of the finished concrete.
Brick sand
Of optimal quality brick sand is generally free of foreign materials and larger aggregates. Still sharp for strength this is a versatile sand to use in concrete mixes where strength and workability are of primary importance.
Washed sand
Commercially all forms of sand should be washed and some forms are even sterilized. Washed sand would generally indicate a lower quality, which means a lower tolerance for aggregate size, where clean washed sand would indicate a higher grade of sand. So long as the sand has not been specifically rounded then it is suitable if not ideal for mixing concrete.
Sharp sand
Refers to sand that has not been tumbled or rounded. Ideal for concrete mixing purposes.
Masonry sand
Masonry sand refers to a sharp, washed sand that will also contain slightly larger aggregates and stones up to approximately ¼ of an inch in diameter. When mixing concrete with larger aggregates such as ¾ inch gravel this sand would be your best choice.
Silica sand
Most commonly found in swimming pool filters silica sand is suitable for concrete purposes as it is sharp, washed and sterilized. However the cost of silica sand is higher than most other grades of sand making it not an ideal choice for concrete mixing.
Proceed to the next section on concrete aggregates - gravel to learn which types of gravel to use and which never to use for making concrete.