Page 31 - GRIHA Manual Volume IV - Introduction to National Rating System
P. 31
22 Griha Manual: Volume 4
1. Use in Portland Pozzolana Cement: This cement is equivalent to OPC (Ordinary Portland
Cement) in mechanical strength, setting, and hardening and is an alternative to OPC,
with an additional advantage of having mild sulphate resistance. Pozzolana cement or
PPC (Portland Pozzolana Cement) is a mixture of ordinary Portland cement (65%–85%)
and a pozzolana (15%–35%). Sometimes, PPC concrete develops strength at a slower
rate than OPC concrete. Calcined clay and fly ash are the most common pozzolana for
PPC. Addition of fly ash significantly improves the quality and durability of the resulting
concrete. There are various companies, which provide PPC, for example, L & T Cement, ACC
Suraksha, Jaypee Buniyaad, Lafarge Cement, and so on. PPC must meet the requirements of
IS 1489:1991.
2. Use in structural concrete: Fly ash and BFS can be used in structural concrete as well. IS
codes recommend the use of PPC cement in structural concrete. Since PPC already has a
certain content of fly ash or BFS, the resulting concrete also contains fly ash or BFS. Ground-
granulated Blast Furnace Slag can also be used to replace aggregates in the concrete mix.
Advantages of using fly ash as a replacement of cement in concrete are as follows.
• Per unit embodied energy of concrete is reduced.
• Use of fly ash increases the workability of concrete.
• Fly ash provides better protection to steel against corrosion.
3. Use in High Volume Fly Ash Concrete (HVFAC): High volume fly ash concrete develops early
strength and workability, in addition to low temperature rise and high ultimate strength.
This is possible due to high dosage of plasticizer and low W/C ratio to the extent of 0.30–0.35
(cement:fly ash:fine and coarse aggregates::1:1.75:3.5) with compressive strength reaching
40–45 Mpa on the 90th day.
4. Ready mix fly ash concrete: Though, ready mix concrete is quite popular in developed
countries, in India it makes up for less than 5% of total cement consumption. Only recently
its application has started growing at a faster rate. In ready mix concrete, various ingredients
and quality parameters are strictly maintained/controlled, which is not possible in the
concrete produced at site and, hence, it can accommodate still higher quantities of fly ash.
5. Cellular light-weight concrete blocks: CLC (Cellular light weight concrete) blocks are substitutes
to bricks and conventional concrete blocks in buildings with density varying from 800 kg/
3
m to 1800 kg/m . The normal constituents of this are foaming agent based technology
3
cement, fly ash (to the extent one-fourth to one-third of total materials constituent), sand,
water, and foam (generated from biodegradable foaming agent). Walling and roofing
panels can also be produced by using CLC.
Advantages of CLC
• Better strength-to-weight ratio.
• Reduction of dead load resulting in saving of steel and cement and reduction in
foundation size.
• Better acoustics and thermal insulation (air conditioning requirement is considerably
reduced).
• Saving in consumption of mortar.
1. Use in Portland Pozzolana Cement: This cement is equivalent to OPC (Ordinary Portland
Cement) in mechanical strength, setting, and hardening and is an alternative to OPC,
with an additional advantage of having mild sulphate resistance. Pozzolana cement or
PPC (Portland Pozzolana Cement) is a mixture of ordinary Portland cement (65%–85%)
and a pozzolana (15%–35%). Sometimes, PPC concrete develops strength at a slower
rate than OPC concrete. Calcined clay and fly ash are the most common pozzolana for
PPC. Addition of fly ash significantly improves the quality and durability of the resulting
concrete. There are various companies, which provide PPC, for example, L & T Cement, ACC
Suraksha, Jaypee Buniyaad, Lafarge Cement, and so on. PPC must meet the requirements of
IS 1489:1991.
2. Use in structural concrete: Fly ash and BFS can be used in structural concrete as well. IS
codes recommend the use of PPC cement in structural concrete. Since PPC already has a
certain content of fly ash or BFS, the resulting concrete also contains fly ash or BFS. Ground-
granulated Blast Furnace Slag can also be used to replace aggregates in the concrete mix.
Advantages of using fly ash as a replacement of cement in concrete are as follows.
• Per unit embodied energy of concrete is reduced.
• Use of fly ash increases the workability of concrete.
• Fly ash provides better protection to steel against corrosion.
3. Use in High Volume Fly Ash Concrete (HVFAC): High volume fly ash concrete develops early
strength and workability, in addition to low temperature rise and high ultimate strength.
This is possible due to high dosage of plasticizer and low W/C ratio to the extent of 0.30–0.35
(cement:fly ash:fine and coarse aggregates::1:1.75:3.5) with compressive strength reaching
40–45 Mpa on the 90th day.
4. Ready mix fly ash concrete: Though, ready mix concrete is quite popular in developed
countries, in India it makes up for less than 5% of total cement consumption. Only recently
its application has started growing at a faster rate. In ready mix concrete, various ingredients
and quality parameters are strictly maintained/controlled, which is not possible in the
concrete produced at site and, hence, it can accommodate still higher quantities of fly ash.
5. Cellular light-weight concrete blocks: CLC (Cellular light weight concrete) blocks are substitutes
to bricks and conventional concrete blocks in buildings with density varying from 800 kg/
3
m to 1800 kg/m . The normal constituents of this are foaming agent based technology
3
cement, fly ash (to the extent one-fourth to one-third of total materials constituent), sand,
water, and foam (generated from biodegradable foaming agent). Walling and roofing
panels can also be produced by using CLC.
Advantages of CLC
• Better strength-to-weight ratio.
• Reduction of dead load resulting in saving of steel and cement and reduction in
foundation size.
• Better acoustics and thermal insulation (air conditioning requirement is considerably
reduced).
• Saving in consumption of mortar.
