Sand Quality AND Curing Compound - Types & Process of Applying
November 02, 2019
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⧪ what is sand ??
➤ Sand is a fundamental crude material utilized in the construction ventures. It is fine total having the molecule size between 150 microns and 4.75 mm.
➤ The nature of sand is as a lot of significance as different materials for concrete.
Testing of Sand Quality at Construction Site:-
Following are the tests for sand at the construction site:
Rubbing Test:-
➤ Rub the example of the sand with wet palms. Great clean sand won't adhere to the hand, while sand with earth will stick and change the shade of the palm.
➤ You have to test it for "residue content" nearby.
Residue Content Test:-
➤ Take a glass of water and include some amount of sand and mix the blend.
➤ Presently enable the blend to settle and watch it following 60 minutes.
➤ Clean sand will settle promptly however on the off chance that it shapes the unmistakable top layer of sediment than sand contains residue or dirt particles.
➤ The thickness of the sediment layer ought not to surpass the thickness of the sand layer by 8 %, on the off chance.
➤ that it contains over 8% the sand ought to be washed with clear water And likewise if fine total containing more than the passable level of residue will be washed in order to bring the sediment content inside admissible breaking points.
Test for Grading of sand:-
➤ The molecule size evaluating of sand for use in mortars will be inside the points of confinement as indicated in Table and For RCC works sand must be coarser and for putting works(zone 4) sand must be better.
➤ See zones of sand for subtleties
➤ Where the evaluating falls outside the points of confinement of a specific reviewing zone of strainers, other than 600 micron IS sifter, by an aggregate sum not surpassing 5 percent, it will be viewed as falling inside that evaluating zone.
Organic Impurities:-
➤ To discover natural contaminations in the sand, you should rehash the procedure of residue substance
➤ test and include scathing pop (salt ) int the glass of water.If the water changes the shading to brown, then there must be some natural pollutions
Visualization Test:-
➤ The size of particles and sharpness of sand (fine totals) is checked by representation.
➤ Sand ought to be free from natural polluting influences (like a shell, shingle, and different contaminations) or they ought to be in limits which are effectively distinguished by the representation
Taste Test:-
➤ You Should taste a spot of sand and on the off chance that it tastes salty, the salt must be available in sand and consequently, it ought not to be utilized at all in any construction. such sand is normally from the stream yet it may be ocean sand or from a region of waterway much.
➤ the time influenced by tidal water close to the ocean.
Earth TEST:-
➤ The nearness of earth in the sand impact the exhibition of the solid quality.
➤ So the nearness of earth in sand can be identified by doing two physical test on sand
➤ Take some measure of sand into your hand and drop it into the glass which contains water.
➤ In the wake of hanging the sand than shake the glass.
➤ If dirt is available in the sand, it will make a different layer over the water surface.
➤ So it demonstrates sand isn't great.
➤ In another basic test take some measure of sand in your grasp and afterward drop it.
➤ If sand stick into your fingers it demonstrates the nearness of mud in sand.
CLAY TEST:-
➤ The nearness of dirt in the sand impact the presentation of the solid quality.
➤ So the nearness of earth in sand can be identified by doing two physical test on sand
➤ Take some measure of sand into your hand and drop it into the glass which contains water.
➤ Subsequent to hanging the sand than shake the glass. In the event that dirt is available in the sand, it will make a different layer over the water surface. So it show sand isn't great.
➤ In another basic test take some measure of sand in your grasp and afterward drop it. In the event that sand stick into you fingers it shows the nearness of mud in sand.
⧪Curing Compound - Types & Process of Applying Curing
⧪ Kinds of Curing compound:-
⧭ Acrylic compound:-
➤ Acrylic is made of polymers of acrylic corrosive. It has Water maintenance Reflectance
⧭ White water wax:-
➤ It will seal the concrete by shaping a film. If we need to go for the next process (Painting, putting and so on )the film can be evacuated by washing it with boiling water.
⧭ Engineered pitch Compound:–
➤ It seals the concrete by framing film. For the next procedure, the film can be evacuated by washing it with high temp water.
⧭ Normal Rubber:-
➤ Forms a layer and seals the concrete firmly and furthermore fills the moment pores present in the concrete
⧭ The procedure of Applying compound
➤ This compound structures a dampness retentive film in the wake of being applied on the crisp concrete surface
➤ This film doesn't enable within dampness to leave concrete consequently, curing happens.
➤ Curing compound is applied when the completing is finished and free water present superficially gets vanished.
➤ The curing compound is applied through showering funnel and sprayer weight is typically 0.5 – 0.7 MPa and spread 300 mm to 500 mm.
➤ This is a huge region like Dams, Airport runways and so forth yet we can likewise utilize brushes or paint rollers to apply curing compounds.
➤ By and large, one liter of curing compound can be splashed for 0.20 – 0.25m2 surface territory of crisp concrete.
➤ At the point when structures are evacuated, the uncovered concrete surface ought to be wetted with water quickly and kept sodden until the curing compound is applied.
➤ On the off chance that water Available go with Direct synthetic compound as quickly as time permits
⧪ Note:-
➤ For greatest useful impact compound must be applied in the wake of completing and when the free water superficially has vanished
⧭ Chiefly Used for:–
➤ This curing compound is truly appropriate for enormous territories of concrete which are legitimately presented to daylight, Large Areas and Skyscalpers:-
Enormous Airport Runways and Skyscrapers
➤ Channel linings, dams and other water system related structures.
➤ Fireplaces, cooling towers, and other tall structures.
➤ Concrete asphalts, air terminal runways, connect decks, modern floors.
⧪ Properties of Concrete Curing compound:-
Water maintenance:- Equalling 0.55 Kg/M2 in 72 hours when applied at 200 Ft.2 per gallon.
Appearance: White fluid
Drying time:- Less than 4 hours concurring ASTM C 309 proviso 10.3
Explicit Gravity:- 1
⧪ Testing of curing compounds:
The curing compounds ought to be tried in agreement to ASTM:
Water maintenance – The Test ought to be directed as per test technique C156.
Reflectance – Determine the sunshine reflectance of white – pigmented compound as per test strategies E97
Drying time – The test ought to be led in agreement to ASTM C 309 provision 10.3