Benefits of Sand layers below the Foundation PCC...
1. River sand layer has more SBC compare to clay or silty soil. Hence it helps the footing load distribute to sub soil uniformly
2. As the SBC of river sand is more it reduces secondary settlement of the structure to some extent ( never zero)
3. It create a uniform leveled surface to take the PCC or Footing
4. Compare to clay or silty soil it reduces Termite entry to the structure
5. If the soil is of having more acidic or alkali sand layer prevent the structure from the deterioration ( increase life period)
a good strong foundation ensures good strong stable ground for a good strong and lasting structure. -- if you build a house on sand and the sand around one of the corners of the house washes away due to rain water falling off your building the building will begin to sink in that corner and the result will eventually begin cascading further along the buildings edges and sides until the entire building is consumed by leaning caused by unstable ground.
Clay, derived naturally, comes from sedimentation in river beds after they become more stagnant. The silt collects and can be cut right from the old stream bed and used for making models and sculptures. Cement, of the Portland variety, is made from sand, rocks and limestone to be used to make buildings and driveways.
Pumiscrete has been used in buildings for many years. It is concrete that uses crushed volcanic rock rather than conventional sand and gravel
generally they pump sand or gravel under house for the footers and the foundation. the sand or gravel helps to make the concrete they are going to pour shift or move less than what it would if it where just on the ground/ dirt, it also creates a barrier from the moisture in dirt. usually depending on state building codes the thickness of the sand or concrete should be between 4" to 12". In cold weather they like to use sand because it does freeze as hard as soil.
As sand is a course granular substances binding agents such as cement and lime can grip to the sand and form stronger bonds - if the mix was all powdery like a cement it would be more line a slurry or even a doh like consistency which would not hold very well under pressure and in weathering. When buildings were first created using mud (wattle and daub) course materials were put in the mix like animal hair and even manure to brake up the slurry like consistency and add strength to the mixure
if you build on sand your house may fall-- but if you build it on a solid foundation it could stand for long periods of time.
Concrete is used for building buildings and it is a mixture of sand, water and cement.
No. Sand is not rigid.
The buildings would flood because if the river floods then the floodplain, a floodplain is flat land that is next to a river, made up of alluvium (sand, silt, and clay). When the river overflows, the floodplain is often under water,will/ would flood too, so if the land floods, then, the buildings and businesses on that land will flood too.
Properties of River SandTextural composition(% by weight)Coarse Sand (4.75 - 2.00 mm)6.6Medium Coarse sand (2.00 - 0.425 mm)73.6Fine sand (0.425 - 0.075 mm)19.8
From the yellow sand in the river.
Clay makes bricks. Sand is used in cement.
The ideal ratio for a sand and cement mix for a strong and durable concrete foundation is typically 3 parts sand to 1 part cement.
The river runs however long, all the while picking up sediment, sand, rocks, etc. and continue doing this for the river's length, and at the very end of the river (mouth), all of this sediment is deposited, leaivng sand at the river mouth.
Maximum value of dry density of river sand is 1.7 gm/cc
plaster sand
Sand Bar