What is Pit sand? - availability, advantage & their use.

Excavation of pit sand (fig. 1)

The sand i.e. procured forming a pit, by excavating normally between 1 meter to 8 meters beneath the earth's surface is termed as pit sand.

The pit sand particles are usually angular in shape with a rough surface and sharp edge as compared to the river sand. Due to the weathering action with the water, river sand particles are mostly round in shape with a smooth edge.

 The pit sand contains more coarse grain size particles by percentage, which makes them the most suitable type of sand for concrete work. However, by sieving and grading, you can use them for all the general-purpose in the construction work.

Pit sand containing coarse grains mixed with sandstones. (fig. 2) 

  The presence of iron oxide provides a pinkish to orange-red color to the pitted sand. (as shown in fig. 3). The oxides form a thin coating over the sand particles, depending upon their presence, giving such irregular variations in the colors. However, you can remove most of them by simply cleaning the sand in the sand washing machine.

Pit sand with varying colors (fig. 3)

 The pit sand does not contain any marine impurities like seashells, chemical salts,  silt deposits, which are more common in the river or sea sand. Sometimes you may find them associated with the clay materials, or some organic impurities which can be removed effectively by sieving and washing them as said earlier.

The pit sand is usually found in the regions having more quartz and sandstones, which gets eroded slowly forming the deposits of the sand layer.

 

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