huangyhg

watertight diaphragm wall joint
i am researching the detailing of a joint between a diaphragm wall and the base slab. the base slab is at -15m, 1,200mm thick and will be cast against the diaphragm walls. my main concern is forming a watertight joint.
the first thought i have is that if we place bend out starter bars in the diaphragm wall when bending the bars out local crushing of the concrete and micro cracks may be formed causing a water path.so maybe couplers are required.
next is the possible leakage at the joint between diaphragm wall panels where there may be a waterpath from under the base slab and around the panel joint on the inside face of the wall.
can anyone point me towards any details on the internet. i have already ordered a book which promises me details, but the more info the better....
are you ok with using waterstops?
i doubt if the type joint you describe has ever been completely waterproofed. the normal course of action is to try your best with a hydrophilic waterstop (see jae's suggestion), but at the same time provide a drainage system adjacent to the wall. this drain will cater for water coming through the slab to wall joint and also the joints in the diaphragm wall.
jae, hokie66
thanks for your input. i agree that 100% watertight may be a high expectation - but a good starting point.
we are considering grouting the diaphragm panel joints on the inside face above and below the base slab.
the main leak path (assuming that the diaphragm walls themselves don't leak - but we will treat that as a separate problem) would then be from the underside of the slab, through the wall/slab construction joint. i have sent a message to the supplier suggested by jae, but yet to see if they have a prescence in s.e. asis.
what about casting in grout tubes so that in case of a leak grout can be pumped in. i have used such tubes for shaft grouting bored piles, but i don't know how the system would work in a construction joint.
i've used blueskin clamped against the concrete surface with an angle and wrapped the blueskin around the angle and cast the concrete against this and it provides a fairly decent seal... i've also used volclay rx bentonite strips...
dik
dik,
volclay rx bentonite strips sounds like a bentonite based product similar to hydrotite hydrophilic waterstop as suggested by jae.
but what is blueskin? i don't like the idea of an "angle" as steel is increasing in price every day. but if the cost is required.....!

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