CIVIL TECH FORUM

  DETAILING OF CANTILEVER BEAM

singhs Reinforced Beam: If main reinforcement is only provided at bottom when concrete at compressionis capable to carry all the compressive stresses. i.e The strain at top fibres are well within limit. Doubly Reinforced Beam: If main reinforcements are provided at top & bottom due to excessive compressive stresses at top fibre of a beam. i.e The strain at top is more as compared to the capacity of concrete at top fibres.

There are several types of roads are there in india  1) Expressways 2) National Highways 3) State Highways 4) Major District Roads 5) Other District Roads 6) Village Roads National thighways connects the major cities of different states. (Across state Boundaries) State Highways connects the major cities within the state along with different states boundaries. Major District Roads connects major places within districtand district boundaries.  Other District Roads connects Taluka places to the district centers. Village Roads which connects villages to the Taluka Centers.

This cement is similar to ordinary Portland cement. As the name indicates it develops strength rapidly and as such it may be more appropriate to call it as high early strength cement. It is pointed out that rapid hardening cement which develops higher rate of development of strength should not be confused with quick-setting cement which only sets quickly. Rapid hardening cement develops at the age of three days, the same strength as that is expected of ordinary Portland cement at seven days. The rapid rate of development of strength is attributed to the higher fineness of grinding (specific surface not less than 3250 sq. cm per gram) and higher C3S and lower C2S content. A higher fineness of cement particles expose greater surface area for action of water and also higher proportion of C3S results in quicker hydration. Consequently, capid hardening cement gives out much greater heat of hydration during the early period. Therefore, rapid hardening cement should not be used in mass concre...

Ordinary Portland cement (OPC) is by far the most important type of cement. All the discussions that we have done in the previous chapter and most of the discussions that are going to be done in the coming chapters relate to OPC. Prior to 1987, there was only one grade of OPC which was governed by IS 269-1976. After 1987 higher grade cements were introduced in India. The OPC was classified into three grades, namely 33 grade, 43 grade and 53 grade depending upon the strength of the cement at 28 days when tested as per IS 4031-1988. If the 28 days strength is not less than 33N/mm2, it is called 33 grade cement, if the strength is not less than 43N/mm2, it is called 43 grade cement, and if the strength is not less then 53 N/mm2, it is called 53 grade cement. But the actual strength obtained by these cements at the factory are much higher than the BIS specifications.

(a) Ordinary Portland Cement (i) Ordinary Portland Cement 33 Grade– IS 269: 1989 (ii) Ordinary Portland Cement 43 Grade– IS 8112: 1989 (iii) Ordinary Portland Cement 53 Grade– IS 12269: 1987 (b) Rapid Hardening Cement – IS 8041: 1990 (c) Extra Rapid Hardening Cement – – (d) Sulphate Resisting Cement – IS 12330: 1988 (e) Portland Slag Cement – IS 455: 1989 (f) Quick Setting Cement – – (g) Super Sulphated Cement – IS 6909: 1990 (h) Low Heat Cement – IS 12600: 1989 (j) Portland Pozzolana Cement – IS 1489 (Part I) 1991 (fly ash based) – IS 1489 (Part II) 1991 (calcined clay based) (k) Air Entraining Cement – – (l) Coloured Cement: White Cement – IS 8042: 1989 (m) Hydrophobic Cement – IS 8043: 1991 (n) Masonry Cement – IS 3466: 1988 (o) Expansive Cement – – (p) Oil Well Cement – IS 8229: 1986 (q) Rediset Cement – – (r) Concrete Sleeper grade Cement – IRS-T40: 1985 (s) High Alumina Cement – IS 6452: 1989 (t) Very High Strength Cement – –