Sand which is also known as fine aggregate. To maintain or check the quality of sand at the site is very important because sand is the most widely used material in the civil engineering construction works. To maintain the quality of cement at the site is very important.
To check the quality of sand at the site, we mainly prefer some physical tests instead of laboratory tests because at the site we don’t have much time. So mainly we perform 5 physical tests on the sand at site.
- Clay Test.
- Organic impurities Test.
- Silt Test.
- Salt Test.
- Earthy Matters.
The presence of clay in the sand effect the performance of the concrete strength. So the presence of clay in sand can be detected by doing two physical test on sand
- Take a some amount of sand in to your hand and drop it in to the glass which contain water. After drooping the sand than shake the glass. If clay is present in the sand it will make a separate layer above the water surface. So it indicate sand is not good.
- In another simple test take some amount of sand in your hand and then drop it. If sand stick in to you fingers it indicate the presence of clay in sand.
ORGANIC IMPURITIES TEST:
To detect the organic impurities in the sand, you may perform this test.
- Take some amount of sand and drop it in to the solution of sodium hydroxide or you may use the solution of caustic soda both work same. After adding sand in to the solution then shake it. If the solution color appear to a brown it indicate the presence of organic impurities in the sand.
Basically presence of silt in the sand is very dangerous because silt reduce the strength of the concrete. To detect the silt presence we mainly perform this basic physical test on sand.
- Take a glass bowl and add some amount of sand into the bowl. After adding sand add some amount of water as well as salt into the bowl and then shake it well. After shaking it leave it for at least 24 hours. If silt is present it will make a separate layer above the sand layer.
To check the presence of salt in the sand we perform very simple and easy test.
- Take very little amount of sand and then taste it. If salts are present in sand it taste will be salty.
EARTHY MATTERS TEST:
The earthy matters are commonly mixed in the sand. So to check the presence of earthy matters in the sand we mainly perform this physical test.
- Take some amount of sand in your hand. After taking sand rub it by using your other hand. If light marks are appear in your hand it indicate the presence of clay.
Note: These all physical test on sand you can perform it at site. But when your experience is increase in upcoming years in construction work you can ably to check the quality of sand without using these tests.