Silt Factor


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Penetration Test for Bitumen IS 1203 1978

Hot the Bitumen in oven 90oc + Softening point and pour in in bowl, approx 10 mm more than expacted penetration. Use bowl depth 35 mm, dia 55 mm size for penetrations below 225 Then keep it in room temp for 1 – 11/2 hours (75 min) Then in water bath at temp 25oc for 1 – 11/2 hours (75 min) Use bowl depth 45 mm, dia 75 mm size for penetrations from 225 to 350 Then keep it in air for  11/2 -2 hours (105 min) Then in water bath at temp 25oc for 11/2 -2 hours (105 min) Then place it under the apparatus Wt of assembly should be 100 g (if 50 gm wt + needle + assembly) Wt of assembly should be 200 g (if 150 g wt + needle + assembly) For CRMB 60 penetration will be <50 Penetration ratio = Penetration at 4oc 200 gm for 60 sec ---------------------------------------------- x 100 Penetration at 25oc 100 gm for 5 sec
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Cement IS 269

cement is used to bind the materials in concrete  The manufacturing process includes Proportioning of raw materials like chalk or limestone,Grinding and burning at 1400-1450OC in rotatory kiln. Due to intense heat the material becomes like spherical balls called clinkers. Gypsum is then added in 3-4%. Cement is formed by grinding the clinkers to required fineness. Tricalcium Silicate (C3S) hardens rapidly and is largely responsible for initial set and early strength. In general, the early strength of portland cement concrete is higher with increased percentages of C3S. Dicalcium Silicate (C2S) hardens slowly and contributes largely to strength increases at ages beyond 7 days. Tricalcium Aluminate (C3A) liberates a large amount of heat during the first few days of hardening and, together with C3S and C2S may somewhat increase the early strength of the hardening cement (this effect being due to the considerable heat of hydration that this compound evolves). It does affect set time...
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Shotcrete

Spraying cement sand mix either in dry form of in wet form by hose with high velocity and pressure at higher elevation surfaces to immediate stick on surface is a shortcrete process. Its also called Gunite. Its used in tunnels or sloped portions. Rapid hardening cement is used.
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