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deck is structural concrete, 4 inches slab with average span of 3 meters. There are drainage holes at the edge of the roof. Waterproof required to prevent water or moisture from seeping down the concrete roof. No equipments on roof. Since it's a roofdeck with 100 psf live load, it can support...

What is the best waterproof material/method to be used on a concrete roofdeck? What is the latest and which do you recommended? Pro and Con? Thanks.

But you stated earlier that "There will be unhydrated cement particles that remain in the concrete after initial curing. If you re-wet the concrete, some of these will hydrate, but they will have little effect on the strength. With hydration though, the durability will improve." And above you...

We always read how strength gain increases through the years and that is why the concrete foundation constantly wet or exposed to water is much stronger (at least not enough to cause heaving or foundation damage from water freezing and expanding or bar corrosions). Is a myth since you said water...

But when you re-wet the concrete months later, it will just be the surface (let's say bare) that gets wet. How would that affect the concrete particles many inches inside the center of a beam for instance Remember you just wet the surface. And I don't think it would be permeable enough to get...

It is recommended to add water to fresh concrete for 7 days to keep it moist and effect good curing. What if it's not done. Can one add water to the concrete 2 months later to continue the chemical reactions that could have stopped because of insufficient water during the 7 days curing period...

There is still load. Imagine you are repairing the column of the ground floor of a 10-storey building, the load of the column below is the axial load of all the columns above. Even if all the floor beams above are shored, the weight still goes to the column of each floor and the column below is...

I'll shore everything. But if eccentric loading in column with only bars remaining can bend, then I'd put 3 times more shore to be sure. Massive amount of shores have to be ordered so I need to know this single fact. Someone wrote in other thread that a column with only bars is equal to no...

If vertical one foot concrete is removed and only bars remaining, and the loading is eccentric at one side of the column. Do you think it's possible the bars can bend to the heavier side? The moment of inertia of just bars are very low and moment magnificant factor can reach 2 even with just 5%...

I need to remove a section of epoxy from a column and need feedback from those with experience. Epoxy seem to drill softer than concrete. Is it normal? This means one can just drill it around rebars to separate the epoxy from bars? What else do you suggest? Picture of the column with epoxy is...

Ok. I will. But some structural engineers I asked forgot about strain compatibility as they only work mainly with rebars and concrete and not composite and haven't come across what I experience. So I need to look for expert in repair. In my school. I remembered the purpose of rebar is to...

I want to compute the different percentages of axial load (factored and nomimal) (by 15% increment) and gauge the deformation length of the epoxy and concrete so as to estimate the crack potential in order to can decide on very expensive process of breaking the epoxy apart and the concrete and...

I just need to know how epoxy interacts with concrete when portions of them added together. When I know how. Then I'll calculate based on the actual geometry and configuration. If anyone has already thought of this.. how the tension in epoxy would affect the surrounding concrete... like would...

http://www.pbase.com/ticaslogos/image/149352082 column damage before epoxy http://www.pbase.com/ticaslogos/image/149352114 column damage after epoxy Ron. I didn't show the larger picture. It's actually worse. See above picture where 4 bars in front are exposed with about 2 inch space behind...

http://www.pbase.com/ticaslogos/image/149351058/original See the above picture.. a corner of a column was hit by a truck. We removed the broken concrete with a rebar exposed at the corner (the rest is perfectly fine as numerous test by engineers have confirmed so this is not a concern in this...

Ron. Of course I know epoxy can't take all the load. Of course. Let's say it's tensile load is only 5000 psi. When tension reaches above 5000 psi for that section, steel with much higher 60,000 psi would take over. What I meant was even if it's concrete or epoxy.. steel will be the final...

So what if epoxy can't transfer its load to rebars more efficiently than concrete. Since epoxy has very ductile failure mode, it can take the load itself. What's the problem with it? Also how thin is "thin section" interfacing with concrete and/or rebar, what if its 2 inches?

Something I don't quite get even after reading the following portion many times (see My questions below) http://mmgrouting.com/foundation.htm "Epoxy grouts cannot be reinforced with rebar like cementitious materials because of the differences in the thermal coefficient of expansion and modulus...

Imagine you have a vertical column and all the loads (beam) are in the right side (eccentric column), the vertical half of the column facing the right side is in compression, the vertical half of the column facing (or left) outside is in tension, does anyone here design column with more...

3000 psi means concrete has compressive strength of 3000 psi. What if the load is very light, like using only the concrete 200 psi. As the load gets heavier, would the column compresses more (and shorten in length in say very tiny 0.001 mm)? Or is there no change in concrete column length due to...