- Swimming Pool Gunite Concrete
- Swimming Pool Shotcrete Concrete
Where the quantity of base slab pool concrete is over 50 m3, it would be advantageous to cast the base slab of the jacuzzi in conventional concrete.
The approved supplier will supply Readymix Concrete conforming to approved mix design.
All reinforced concrete will be placed in-situ, using concrete placing pumps, crane+skip, chute or other approved transporting/ placing devices as necessary. Concrete will be carefully compacted when placed to ensure a dense and uniform mass free from air holes and cavities. The vibrators will be of plunger (poker) type with mechanical vibration for insertion in the concrete. Extra precaution should be taken to properly vibrate concrete adjacent to the expansion joints and congested areas of rebars.
After the concrete has begun to harden it should be protected from quick drying with hessian sheeting, wetted and covered with 1 layer of the 500g-polythene sheet.
Curing of the concrete (without cement replacements) will be continued for a minimum of 7 days from the time of casting. Pneumatically placed concrete (swimming pool gunite/pool shotcrete) will also be cured as mentioned above.
The following equipment will be kept in good condition at all times for testing of concrete:
- Six numbers 150mm cube moulds.
- Slump cone.
The testing of concrete will be as per the relevant specification requirements.
During the laying of the base slab when concrete is partially hardened, (1 or 2 hours after laying) the surface in the wall area will be scrubbed with wire or hard brush removing any laitance. Care should be taken that pieces of aggregate are not dislodged.
The top of the base slab will be scarified using a nylon/ wire brush immediately after all surface bleed water has disappeared or when the concrete can sustain foot traffic. (FOR FUTURE FINISHES)
POOL GUNITE/ POOL SHOTCRETE
Setting out Survey:
After completion of the reinforcement and jacuzzi fittings in the pool structures and prior to the commencement of the swimming pool gunite, setting out points shall be re-established and rechecked by all parties concerned (i.e. MC, CONSL) to ensure compliance with the dimensions, squares, level etc. as per the final finish requirements.
An approved mix design shall be used for effecting these works. All materials used for guniting shall be submitted under materials submittal and approved prior to commencing the works.
All operators will have a minimum of 3 years experience of their trade.
Prior to starting the guniting works provisions will be made so as not to damage/contaminate any surrounding areas. The surrounding areas will be protected as follows:
- erect screens with plywood, tarpaulin or polythene sheets where required to avoid damage by overspray.
- limit working and storage areas
- provide machinery/manpower for removal of rebound and storing in an approved area prior to legally disposing of it off-site.
Guniting/Shotcreting operations will commence at 7.00 a.m. and continue through the working hours – suitability of weather permitting. Day joints will be left at approx. 45 deg. angle and scarified with a sharp-toothed trowel to ensure proper bonding at the joints. Before starting the spraying on the next day the entire joint will be thoroughly cleaned and wetted. Any rebound / lose material will be completely cleaned and removed. Swimming pool gunite once partially stiff will be cut to the required profile with a sharp-toothed trowel. Rebound/waste will be collected and disposed of off-site.
After the swimming pool gunite has begun to harden it should be protected from quick drying with hessian sheeting and wetted continuously. Curing of the gunite will be continued for a minimum of 7 days from the time of casting.