Cement

PPC Cement(Portland-Pozzolana Cement) :-

PPC Cement(Portland-pozzolana cement) produce less heat of hydration and offers greater resistance to the attack of impurities in water, than normal portland cement.It is particularly useful in marine and hydraulic structures.The cement can generally be used whenever ordinary cement is usable under normal conditions.However ,all the need not necessarily contribute to the strength early ages. IS 1489-1976 gives the specification for the production of equivalent to ordinary portland cement on the basis of 7 days compressive strength.The comprehensive strength of portland pozzola cement at 28 days also has been specified to enable the porland-pozzolana cement be used as substitute for ordinary portland cement in plain and reinforced concrete works.The portland pozzolana cement should confirm to the requirements specified in IS 1489-1976.    

The average compressive strength of mortar cubes(area of face 50 sq cm) composed of one part of cement,three part of sand (conforming to IS;650-1966) by mass and p/4+3 percent(of combine mass of sand and cement)water obtained in manner described in IS:4031-1968 should be as follows:

(i) at 168+_ 2h      22  N/sq mm, minimum

(ii) at 672+- 4 h      31 N/ sqmm, Minimum

where p is the percentage of water to produce a paste of standard consistency.