The document discusses new materials and technologies used by CPWD in Mumbai, including post-tensioned slabs, autoclaved aerated concrete blocks, glass fiber reinforced concrete panels, stamped finish concrete, geofoam flooring, acoustic false ceilings, double stack car parking, solar panels, and energy efficient designs. Post-tensioned slabs provide material savings and reduced dead load. Projects using these include the CBI office building and buildings under construction at the Income Tax office and IDBI.

1. USE OF NEW MATERIALS AND
TECHNOLOGIES BY CPWD AT MUMBAI
DR K M SONI
CHIEF ENGINEER, CPWD, MUMBAI

2. Post Tensioned Slabs
• POST TENSIONED SLABS
– CBI OFFICE BUILDING
– NISM BUILDINGS (PARTLY)
– INCOME TAX BUILDING UNDER CONSTRUCTION
– IDBI BUILDING UNDER CONSTRUCTION

6. Advantages of PT Slab
• Material Savings
• Reduction in concrete is due to thinner
concrete members.
• Reduction in rebar in floor elements.
• Reduction in dead load resulting into saving in
concrete and reinforcement of structural
members including foundation.
• Saving in building cladding, vertical
mechanical/service elements, rebar and
concrete in shear walls and other materials
due to lesser sizes.

7. Steps in construction
• Design
– The existing design has been based on Presscrete Post-Tensioning System (PPS). Concrete in
one member panel shall be placed in one operation continuously without interruption.
• Concreting
– Care is taken that the pre-stressing tendons do not get displaced or damaged prior to casting
and during casting. It is ensured that discharge of concrete is not directed onto the pre-
stressing tendons. Vibrating is avoided from coming into contact with the pre-stressing
tendons whenever possible. Proper compaction of the concrete in anchorage areas is ensured
due to high local stresses in these areas and care taken that all the grout hoses remain
exposed and protruding from the concrete surface.
• Stressing
– After concreting, the carpenter removes the vertical sides end form work. All the stressing
recesses are cleared and pre-stressing barrels and wedges fixed to all pre-stressing castings.
When concrete has reached the transfer strength as per the shop drawings (from the results
of cube tests), stressing of cables is carried out. All cables are tensioned to the required
jacking force and monitored through the pressure gauges.
• Grouting
– Excess cable length is cut after the stressing. All pre-stressing tendons are ensured to be
flushed with clean water. Grout is mixed according to the design mix for at least two minutes
until a colloidal consistency is produced. The water is put into the container first and the
cement is then slowly added. When the cement and water are thoroughly mixed, the non-
shrink additive added to the mix. The grout then is injected into the pre-stressing tendons.
Grouting is carried out by injection at one end of the duct until clear grout flows out from the
other end. The grout hose at the both end is then sealed. Grouting works commence when all
scaffolds at a particular storey where grouting works are to be carried out, are removed.

8. Limitations
• Since the cables or tendons in the slab have
been stretched to high tensile strengths, it is
extremely important that the slab is not
drilled, cut, chiselled or disturb in a way so as
to expose the tendons

13. AAC BLOCKS
• LOW DENSITY
• GREEN MATERIAL

14. Service trenches
• Not a very new concept
• Being adopted in NISM

15. GFRC PANELS IN FACADE
• Can be manufactured in many shapes
• Can be painted

17. STAMPED FINISH CONCRETE
• Can be achieved in desired colours
• The process includes
– preparation of sub-grade,
– placing of forms,
– providing reinforcement for stability,
– placing the concrete,
– screeding and finishing the concrete,
– applying colour and
– stamping the concrete using desired moulds.

18. Stamped finish concrete

20. Innovative Floorings
• Wood plastic composite flooring,
• Maple hardwood sports flooring for special
applications,
• Geofoam block flooring
• Crazy patterned flooring of leather finish,
flamed and polished granite
• Italian marble flooring

21. GEOFOAMFLOORING IN STEPS

23. Seating arrangement of class rooms

26. Innovative False Ceiling
• Acoustic false ceiling
• Cloud acoustic false ceiling

27. ACCOUSTIC FALSE CEILING
• Anutone False ceiling

31. Double Stack Car Parking

32. Glass
• Structural Glazing
• Partitions
• Fire resistant Lobbies
• Doors
• Murals
• Solar PV Panels

37. Dry Stone Cladding

38. STP

39. SOLAR ROOF TOP PANELS

40. AHU ON TOILET SLAB

41. SYNTHETIC GRASS

42. FOLDABLE PARTITION

43. LOUVERS

44. Energy efficiency
• In new buildings only LED fitting or energy
efficient T5 fittings are provided.
• Energy efficient Chillers are provided
• Solar roof top PV Panels
• Recycling waste water
• Rain water harvesting

45. Pumping system
• CPWD has adopted hydro-pneumatic
pumping system for water supply in most of
large projects.

46. Green buildings
• CPWD is constructing all green buildings and
getting them rated in Mumbai
• CBI – 4 star GRIHA
• IDBI Belapur – 3 star GRIHA
• NISM – 4 star GRIHA
• NTH – 3 star GRIHA
• Income Tax Building – 4 star GRIHA

47. CBI OFFICE
BUILDING

48. NATIONAL INSTITUTE OF SECURITIES MARKETS

49. Student and MDP Hostel blocks
Residential Block
NISM: Images
Orientation Block
Academic Block Amphitheater
Hostel & MDP Block
Landscape development
Orientation Block