Ways to recognize good sand and sand field test
Sand is a granular material composed of finely divided rocks and mineral particles. Sand has different structures but it is defined by its grain size. Sand grains are smaller than gravel but thicker than silt. May also refer to a textural class such as sand, clay, or clay; That is, sand particles with more than 85% of the mass of the soil are referred to as sand.
Sand can usually be divided into three parts
- Peat sand
- River sand
- Sea sand
1. Peat sand:
This type of sand is obtained by digging holes in the ground. Which is smooth, angular, and free from harmful salts. This type of sand is usually used for mortar.
2. River sand:
This type of sand is found on the banks of rivers. Which becomes thin and round. It is finer than peat sand so this sand is used in the work of plastering.
3. Sea sand:
This type of sand is found on the coast of the sea. Which is as smooth and round as river sand. However, this type of sand contains harmful salts.
Coarse-grained sand
This type of sand grain is relatively slightly larger in size so it is very suitable for casting during construction. Sylhet sand is equal to making concrete.
Warning on the use of sand
There can be no dirt or clay with sand. Saline sand should not be used and the sand should be washed thoroughly before construction work to remove mud, salt, dirt, weeds, stalks, pebbles attached to the sand.
There are three types of sand in the conventional way:
Viti Sand: The FM of VT Sand is 0.5 to 0.7 Used for filling. It is the lowest of the sand quality. Basically, this sand has no specific size or any FM. Dirt and soil are mixed and somewhat black in color. This sand is mainly used for filling house-grade beams and foundations. Almost every house has something elevated. This VT sand is used for this elevation. These are sold as per car. Try not to take small cars. Use large dump trucks. This will save a lot of money.
Local sand: Its FM is 1.2 to 1.8 Used in masonry, plastering. It is basically fresh white sand. This sand is mainly used for casting. It is mixed with ordinary red sand or Sylhet sand. Talking about this sand in the market, many people supply many types of sand. But the reality is that very few suppliers have the real sand. Usually, this sand is collected in a completely natural way. So exactly where the sand collection is coming from is a very important issue. So before buying sand, find out which area you are buying sand from. Generally, the sand of Bhuapur is the best in Dhaka.
Coarse sand: Coarse sand is more common in Sylhet. Its FM is 2.3 to 2.8. Used in welding. The reason this sand is called red sand is that its color is red. And its main supply comes from Sylhet. This sand is found in several areas of Sylhet including Bholaganj and Bisnakandi. This sand is also found in Mymensingh region. Make sure you have a large car when buying. Because locally some of these sand sands are of quite poor quality. These include sand with mud and soil, including gurus of dead stones.
Angular sand is better than round sand. Coarse sand is good for casting. The sand is called fine aggregate. The sand should be clean and free of mud.
Use of sand in construction work and sand field testing
- Before using sand in construction work, it is necessary to ensure that there is no dirt or clay through sand field test. Sand should be washed thoroughly before construction so that mud, dirt, weeds, stalks and pebbles attached to the sand are removed.
- In some cases the quality can be easily identified by the test. Such as:
A) If sand is rubbed on the palm of one hand with the other hand, if dirt gets on the palm of the hand, then it should be understood that sand is not good.
B) Salinity can be tested with a little sand in the mouth.
- After shaking it in a glass filled with 1/4 part sand and 3/4 part water, it is decided that if the sand level is very low, then the sand is good. Although colorless, it will be marked as good sand.
4. Add a little sand with 3% caustic soda solution and shake it in a bottle for 24 hours. If the color of the substance stored in the bottle changes to brown, then it must be understood that chemicals are present in the sand.
5. We bring sand to the site by truck. Many times less educated people take this sand. That person should understand that one truck of wet sand weighs more than one truck of dry sand. So at night, the sand site must actually see it dry/wet. This is because mixing water with completely dry sand increases the volume of sand. As a result of this increase, we will get less sand in quantity.
6. After purification with water on-site, it should be dried first. When wet sand is used in construction, it reduces durability.
7. The grading of sand grains is calculated in the laboratory. The results of this test are published by Fineness Modulus (FM). FM of fine sand suitable for construction work should be 1.2 to 1.5.