Browse Forums Paving & Concreting 1 Apr 13, 2020 10:16 pm Hi Everyone, Im new to the forum. Im building a large underground water tank on my property. its is approx 200,000L Tank. Im wondering when it comes time for concrete. should i use 32 mpa or 25mpa concrete and is there a some kind of special additive for concrete that is designed for watertanks? the dimentions are 10x7.5x2.4meters (Rectangle water tank). Any advice would be great. thanks. Re: Concrete Watertank build 2Apr 14, 2020 11:03 am 32 MPA concrete has more cement, it is stronger and denser and more waterproof, I used it on tilt up factories. You have to pour concrete into forms and avoid honeycombing and vibration is one method but make sure your concrete slump is at least 100. Alternatively you can use additive similar to "super flow" which makes concrete almost self levelling but your formwork must be good, no leaks. Foremost Building Expert in Australia,assisting with building problems/disputes, building stage inspections,pre-contract review advice for peace of mind 200 blogs http://www.buildingexpert.net.au/blog Re: Concrete Watertank build 4Apr 15, 2020 10:25 am Thanks for the responce guys. Yes i have looked into dincel but i thought it was too expencive and i went for the 17mm form ply instead. I found the ply second hand for $15 per sheet and it works out nicly because the tank is exactly 1 vertical sheet tall. I think ill go with the 32mpa as i orignally though but i dont think ill add anything to make it more watery. My plan was to just tap the exterior of the formwork to make sure there is no air pockets in the concrete. Re: Concrete Watertank build 5Apr 15, 2020 10:50 am Hire a concrete vibe when you pour. Just hitting the form won't always do it. Are you going to pump it? Accessible Carpentry & Cabinets accessiblecarpentry@gmail.com accessiblecarpentry.com.au https://www.facebook.com/pages/Accessible-Carpentry-Cabinets/583314911709039 Re: Concrete Watertank build 7Apr 15, 2020 8:05 pm Consider adding Radmyx to your concrete which will waterproof it for lifetime. It is easy process and Radmyx can be added during the pour. https://www.radcrete.com.au/product/radmyx-capillary-waterproofing I used it to waterproof my slab and footings and it works like chime. Re: Concrete Watertank build 8Apr 16, 2020 3:39 am Thanks again everyone. yes I am getting a pump in to do it and ive got about 3 mates and my dad to help 1 profesional concretor. I Have a vibrator but i dont think it will help that much as it wont be long enough to get to the bottom of the formwork walls. but i will use it where ever I can. Also i have spoken to the concrete supply company and they said it will cost me $215 per cubic meter of 32mpa without waterproofing additive or $275 with the additive. Apparently they mix it in when they make the concrete. That seemed alot more expencive to me tho. Would love to hear thoughts about those prices. Ultimately I was going to paint the inside of the tank with a waterproof tank lining once the concrete cures so i thought I might skip the additive as it would be an additional $2280.00 to put the additive in all that concrete. Thank you so much everyone. This all makes a lot of sense. I guess when you talk to a builder who butters up everything to look very polished, you get to start believing… 7 18306 Hi all I need a guidance on how far I need to space expansion joints in the concrete driveway and its type (keyway/foam.) Contraction joints are at 3m max for a 125 slab. Thanks 0 11018 |