I’m filling in cracks in my porch’s ‘cement’, though I’m not SURE it is actual cement. Does anyone know if there is a difference, between all of the substances, cement, concrete and/mortar?
I’m * using * ‘cement’ in a cylinder with my caulking gun, but, I’ve noticed substance differences. One being very thick, and another that came in a bigger, rounder container which you just squeeze, is more runny. The thinner ‘cement’ CAN NOT be used vertically to fill in cracks, only the thick stuff using the caulking gun can be used there.
I am not sure how mortar differs from the other 2, but concrete contains cement, sand and some kind of rock like gravel or aggregate. Portland cement is the binding agent in concrete and it can be used by itself without sand or rock and in that case it is referred to strictly as cement though many people call concrete “cement”.
Cement is one of the ingredients in concrete or morter (along with sand and water). I’m not sure of the specific difference between concrete and morter, but I believe they have a different ratio of ingredients and different consistency.
Mortar contains more lime and sand in ratio to cement than does concrete so that it may be worked with a trowel and thick enough to hold up bricks, stones, etc.
Here’s my guess. Cement is the bonding agent that holds it all together, when mixed with water and used alone, it really doesn’t have much strength. Concrete adds sand and/or gravel which the cement leaches into and forms a chemical bond which makes the whole much stronger than the sum of the parts. Mortar (or mud) is used to connect bricks or cinder blocks so anything as large as gravel is impractical, so the cement is mixed only with sand. It’s been a long time since I’ve played the part of sand-shoveling grunt so feel free to correct me.
Everyone is pretty much on the money with this, except that ‘cement’ is a broader category than what is usually referred to in the context of mixing concrete. Anything you squeeze out of a tube is extremely unlikely to be portland cement, as portland will cure in moisture unless it is kept fluid, as in a cement mixer. It will even cure underwater. Besides portland cement, there are roofinf cements, rubber cements, etc. which are basically just descriptive of their use.
A porch floor is most likely to be (under)reinforced concrete. It is not necessary to fill the cracks with an identical mixture and you would be safe to use any product advertised for that purpose, as the result is merely visual. The best idea would be to find something that (when dry!) matches the color and texture of your porch – and make sure that it doesn’t expand or contract at a substantially different rate than the slab. Lime mortars tend to be more forgiving in this regard as they stay relatively soft.
[[A porch floor is most likely to be (under)reinforced concrete. It is not necessary to fill the cracks with an identical mixture and you would be safe to use any product advertised for that purpose, as the result is merely visual.]]
Dystopos, I called it a ‘porch’ when it is actually the steps and landing before one opens my front door.
[[ and make sure that it doesn’t expand or contract at a substantially different rate than the slab. Lime mortars tend to be more forgiving in this regard as they stay relatively soft.]]
Okay, your last statement is really more on target with my question. I’ve still got a few more cylinders of ‘cement’ caulk, but, it isn’t as adhesive as I would wish for, though it does * look nice when it dries. * I’m just tired of going through every season with having to do this again. Thanks for you help!
The steps and landing are probably precast concrete which might be a higher strength material with a minimum of reinforcing if any. If the cracks are increasing in size rather than just recurring in the same place, then the concrete is inadequate to the task at hand, either structurally or in resistance to weathering. If this is the case, the correct solution would be to replace them, although there is unlikely to be any dangerous collapse, just a relentless spread of cracks until it’s painfully obvious. If you really want to seal the cracks (which is still not "repairing: them) you should use an epoxy. Epoxies for masonry repair will usually have some sand in them to mimic the concrete texture, but the color will be all wrong. I would suggest the best short-term patch would be a lime mortar, but you can’t stop it from working loose over time. A more cementitous mixture will make a longer lasting patch, but will shorten the life of the steps themselves, although it may be negligible. Good luck.
‘Epoxies for masonry’, okay I think I’ve got my mind around the name! I believe it is just regular weathering with the way our house faces, the door was a killer with fading from the direct sun, until I installed a storm glass door. It seems to have helped, but the steps, I’m still struggling! But when I go to Home Depot next (I almost live there!) time, I’ll read the ingredients on the caulk looking for the lime basing you mentioned. Thanks so much for your help, and for wishing me luck!
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I have never heard this word and can’t find it in the dictionary, but I love it and will definately add it to my construction vocabulary.
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I have never heard this word and can’t find it in the dictionary, but I love it and will definately add it to my construction vocabulary.
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Oh, it’s a word alright. I just found out I’ve been mispronouncing it, though.
cem-en-ti’-tious (-tish’us) a. [L. caementitius, pertaining to quarried stones; from caementum, rough stone, stone chippings.] Pertaining to cement; having the quality of cementing; of the nature of cement.
(from my trusty 1936 Websters Universal Unabridged)
–oh, and Anti Pro… I doubt you’ll find lime mortar in a squeeze tube. It usually comes dry in bags as it’s difficult to prevent it from curing once it’s wet. I think you can get small quantities in a carton that looks like a milk carton. Read the label on the stuff marketed as ‘floor leveler’ and see if it might do the trick.
A few things you might want to do before applying any repair materials: First, if the cracks are narrow (less than a half inch), you’ll want to rout them out. It would seem odd to make them wider, but it helps the repair material get a good hold so it won’t “pop” out. Then you want to brush the area with a wire brush to clean out any loose material.
There are several products that are specifically made for this application, I’ve spec’d products by Sika Corp. and W.R. Grace (not for the squeamish - they’re the bad guys in “A Civil Action”). Either should be available from your local builders’ supply, if not Home Depot. Make sure that what you get is either “non-shrink” or “shrinkage-comnpensating”
