Work method Statement for IPS and Tremix Flooring (VDF)

Work method Statement for IPS and Tremix Flooring (VDF)

SCOPE/PURPOSE
This procedure covers the methodology to be followed for carrying out IPS Flooring in line with the approved technical specifications.


CODES / SPECIFICATION
IS 2571 Laying of in-situ cement concrete flooring


RESPONSIBILITY
Responsibilities of all concerned is clearly mentioned with respect to overall administration and implementation in the approved Organogram.


MATERIALS TO BE USED
Concrete with 20 mm down coarse aggregate. Panels: Steel flats of 75 mm thickness, 6 m in length.


SAFETY REQUIREMENT
The worker must wear proper safety appliances like shoes, goggles, cotton gloves, helmets, shoes etc during surface preparation.
Workers would wear gumboots and hand gloves during concreting
Proper illumination to be provided during the work, if required.


DEPLOYMENT OF EQUIPMENT
As per the requirement and the direction of Project Manager.


DEPLOYMENT OF LABOUR
As per the requirement and the direction of Project Manager.


IMPLEMENTATION

Surface preparation:
Clearing all dirt and loose matter
Chipping and clearing of mortar dropping.
Do prepare the surface on the concrete floor by hacking at close intervals (50 to 70 mm center to center) with bush hammer or with a chisel and hammer and then wash it thoroughly with water. This will roughen up the concrete surfaces and ensure a good bond is provided for the IPS concrete.
The surface thus prepared should be uniform, clean and saturated with water for minimum of 4 hours before concreting.


Laying Procedure:
  • Fix the panels dividers (as mentioned in the drawing) in position for diagonally alternative panels. The panel’s size should not be more that 6 M X 3 M (18 Sqm).
  • Dividing strips of PVC/Glass/MS shall be fixed as per the panel layout to correct line and level. Top of the strip must match with the required slope and finished floor level. Strip fixing can be done with mortar at least one day in advance.
  • Do the concreting in the sequence of laying in alternative panels.
  • Before starting IPS concrete laid/spread the cement slurry (1 cement : 4 water) on the surface.
  • Base coarse concrete of given thickness shall be finished rough in first stage. Top 10 to 12 mm thick second layer concrete needs a richer mix with zero fines. (i.e rich mix as specified with only 6 mm aggregate, cement and hardener if recommended. No sand to be used.)
  • Pour the concrete in the panels, Level and compact the concrete with Double beam vibrator, to give dense and flat surface.
  • Start power floater for grinding the surface (along with leveling it also increases the water resistance of concrete flooring).
  • After completion of concrete check level maintain proper level on the surface.
  • Use the power trowels to give desired smooth finish.
  • Finish the top surface with Broom, to get required broom finish.
  • For all trowel finished surfaces, the finishing has to be completed before the mortar or concrete is fully set.

Carrying out curing for specified period of 7 days.
If needed Groove cutting to be done at required places.


WORK PROCEDURE FOR TREMIX FLOORING
  • Initial suitable layout of construction joints and isolation joints shall be decided prior to start of Tremix flooring.
  • The surface of the guide channels (on which the surface vibrator is supported), shall be cleaned from concrete. Align the guide channels to true required level. Panel casting layout shall be strictly followed as per step 1.
  • Concrete shall be placed and distributed evenly and as near the final level as possible.
  • Concrete will be vibrated with an immersion vibrator in front of screed vibrator. Heaping of concrete in front of screed vibrator will be avoided.
  • Ensure that the areas close to channels and stop ends are carefully vibrated. Ensure not to distribute the concrete with the poker vibrator as it would create a risk of over vibration and segregation.
  • Surface vibration should start as soon as there is enough concrete in front of the screed vibrator. Screed Vibrator is to be pulled from both ends.
  • Vacuum dewatering process must start within 30 minutes from the time of start of concrete pouring.
  • The filter pads are placed in such a way that there is atleast 100 mm (4”) fresh concrete visible around the filter pads on all four sides. Filter pads should be overlapped with each other by at least 250 mm (10”).
  • Suction pad must be rolled open over the filter pads and dewatering must then start. Extent of dewatering is related to thickness of floor concrete i.e. average 4 min. per inch thickness OR
  • physical check of dewatered surface which should not give foot print while walking to be seen. Excess/less dewatering not advisable.
  • While repeating dewatering process subsequently, suction pad must be rolled out atleast 300 mm over the vacuum dewatered area. Before spreading the suction pad on dewatered area, it is essential to give one pass of skim floater (with the disc) along the edge of the dewatered concrete.
  • The central pipe of the suction pad shall be the suction house which in turn shall be connected to the vacuum pump. When the pump is started, vacuum will be created between the top cover and filter pads. Excess water from the concrete will be taken into the vacuum pump tank and discharged through a pipe away from fresh panel.
  • After Vacuum Dewatering, scrapping operation shall be made diagonally in two directions over the concrete surface.
  • The concrete which is collected during scrapping shall be used for adjusting small surface irregularities of the vacuum treated surface.
  • The first finishing operation shall be done by floating with the skim floater attached with a disc.The second finishing operation shall be troweling with skim floater attached with the troweling blades. Normally, troweling is to be continued till the smooth surface finish is achieved without floater marks.

Curing can be done by ponding, covering with plastic sheets or gunny bags. Curing must be done for atleast 7 days.

Groove cutting for construction joints or isolation joints shall follow the sequence of tremix flooring without much time lapse.
Groove filling can be done with any elastometric material subsequently. Groove cleaning and drying needs to be ensured.
 
Hi.

Absolutely a fine description. Kudos to you for this as VDF has been dominating industry for quiet some time . Very recently I have carried out VDF flooring for a FMCG client at Pune and had a bizarre experience after 1-2 months, when they started operating the warehouse. The total area of the flooring ~ 40000 Sqm and the panel size was 45x 4 m(180 Sq.).After a month or two when the floor become operational , it has been noted that cracks had been developing and getting widened at its edges where we fixed the channel to support the frames. Prior to handing over the floors, grooves were cut for expansion and contraction joints and filled with PS even then , the cracks were happening to the edges and this was getting widened further. What could be the reason ? Before cutting the grooves, we ensured normal separation occurs between the panels so that grooves are formed on the exact location. What could be the reason for this crack developments? Its was not on isolated areas but almost 30 % of area randomly!
 

Pawan Dhagate

Staff member
Hi.

Absolutely a fine description. Kudos to you for this as VDF has been dominating industry for quiet some time . Very recently I have carried out VDF flooring for a FMCG client at Pune and had a bizarre experience after 1-2 months, when they started operating the warehouse. The total area of the flooring ~ 40000 Sqm and the panel size was 45x 4 m(180 Sq.).After a month or two when the floor become operational , it has been noted that cracks had been developing and getting widened at its edges where we fixed the channel to support the frames. Prior to handing over the floors, grooves were cut for expansion and contraction joints and filled with PS even then , the cracks were happening to the edges and this was getting widened further. What could be the reason ? Before cutting the grooves, we ensured normal separation occurs between the panels so that grooves are formed on the exact location. What could be the reason for this crack developments? Its was not on isolated areas but almost 30 % of area randomly!

Sir ,

In your case following can be probable reason which lead to cracks
1) Delayed curing
2) More fines in the concrete mix
3) water cement ratio might have changed
4) Gaps or interval for unloading n placing concrete
5) overdose of admixtures
6) Rise in temperature as it is not clear whether room was isolated completely or partially .


I hope this may help you to investigate and analyse your situation at site .

Regards

Civil4m
 
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Reactions: Vinod Achtani
Sir ,

In your case following can be probable reason which lead to cracks
1) Delayed curing- We ensured Curing and that too immediately
2) More fines in the concrete mix: Valid Point
3) water cement ratio might have changed: RMC reports doesn't show any deviation
4) Gaps or interval for unloading n placing concrete:
5) overdose of admixtures : RMC reports doesn't show any deviation
6) Rise in temperature as it is not clear whether room was isolated completely or partially .: Activity had been done inside a shed and the roofing was in place


I hope this may help you to investigate and analyse your situation at site .

Regards

Civil4m