Transcript
Types of cement:
1. Ordinary portland based cement
2. non opc cement
Ordinaray portland cement• Rapid hardening cement• Low heat portland
cement• Sulphate resisting
cement• Masonary cement• Water proof portland
cement• White portland cement• Coloured portland
cement
Rapid hardening cement
• Finer than opc provide greater surface area for action with water
• Gain strength early• 1 day strength of this cement is
equal to 3 day srength of 43 grade cement
• Used where a rapid strength devlopment is required
• Rapid strength gain is accomplained by higher rate of heat devlopment useful in cold enviourment concereting
• Not suitable for hot concereting • Prefebricated structure
Low heat portland• Less recative than
opc• Initial setting time is
greater than opc• Slow devlopment• Used in mass
concereting:dam• Slow devlopment of
strength less heat
Sulphate resisting cement• Contain silicate content
is called sulphate resisting cement• Expansion within
hardned structure of cement paste result in crack is called sulphate attack
• Used marine enviourment
Masonary cement• Finely gridned• Produce
smooth ,plastic surface
Water proof cement• Water proof
substance is added in opc• Calcium
sterate,aluminium sterate,gypsum with tannic acid
White portland cement• Amount of iron oxide
governing greyiesh colour is reduced• Chalk,highly purified
lime stone as raw material• Finer than gray
cement• Used to minimise
temperature effect
Coloured portland cement• Pigment is added for
achiving different colours• 10% pigment is added• Permanent pigment
should be used so that colour remains for a long time• For decoration
purpose
Non portland based cement• High alumina cement• Super sulphate
cement
High alumina cement• Very rective• Very high early
strength• 80% at 24 hours• Resestive to chemical
attack• Rise of temperature
Super phasphate cement• Made by mixing 80-85%
well granulated slag with 20% sulphate
• Initial setting time 2.5-4 hours,final setting time4.5 to 7 hours
• Heat of hydration is very low
• Used in foundation which is used in aggressive condition
• Requires great care when used in cold weather