Browse Forums Landscape & Garden Design 1 Mar 15, 2015 11:10 pm So we recently had some plain concrete done around our house, is it normal to have these cracks? Also I find the concrete that was done seems very dusty, white grey dust. Seem to have missed something on it. Am I suppose to water it down ? Cheers Re: Concrete advice - small cracks and dusty 2Mar 16, 2015 8:43 am No that crack is where the forms were lifted to early and vertically not away from the edge. The concreter will be aware of this defect. It could be repaired with resin, though that would depend on the aesthetics and the prominence of that section. That whole edge looks pretty bad. With no effort applied to the finishing of that edge with a rolling/edging tool it looks poorly 'closed off' and will be weak for ever more. Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 3Mar 16, 2015 9:13 am I do have other cracks as well which is more linear. Is it normal to have some cracks? Will have to get on with the concreter... What about the dusty phenomenon? Re: Concrete advice - small cracks and dusty 4Mar 16, 2015 9:37 am Well to me it looks like they used a lot of water to finish... but as I wasn't there and likely a number of reasons, but looking at the photos and the poor edge finish, I just don't think it was finished('closed off') sufficiently. Not enough cement 'drawn' to the surface. If it was hot and the case was, water was used, then a (x)% of cement was washed out of the top few mm resulting in deficient cement content. Was the concrete mix 20mpa? (20/20/80) Where the path is will be how you deal with it. If the aggression of the surface is good (textured) for slip resistance and the path is on the south side with minimal sun, moss will grow. Sodium hypo occasionally will help this. If you want to stop if from 'dusting off' then without creating a maintenance issue and sealing it with paint or other topical coating that will wear out and require more painting. You could acid etch it and this will release a lot of loose particles that 'abraid' off over time( called dust LOL) and should reduce dusting off considerably. Or remove and replace Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 6Mar 16, 2015 12:02 pm Correct, the link is down for a while. I should/will remove it. I'm in Sydney currently, but have worked in most states. My early hobby/first job was with the fibreglass industry a couple of years (surfboards/boats etc) but my trade is concrete finishing and later became waterproofing with a tree change in 1989 repairing concrete for mining and industrial, then wineries, breweries dairy farms etc covering about 35 years. My home is a long way away on the south coast of wa. I am hoping to have an op on my back soon and get back to work... a bit dull and dreary So again found time to share some info that I seem to have picked up over a few summers lol There are a few photos here http://s670.photobucket.com/user/onc_ar ... t=6&page=1 of some amusing things... and some work stuff. Have fun... PS there has been a long time between me posting new photos... but I have plenty if you want to see some Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 7Mar 16, 2015 12:32 pm You have some interesting photos there. I saw a couple of exposed agg drives. Are you a fan of sealing the exposed agg concrete? Are you a fan of the Connelly key joint for contraction and for construction joints? Do you place a hand joint ontop of the Connelly key joint or does the key form the joint to the surface of finished concrete? Re: Concrete advice - small cracks and dusty 8Mar 16, 2015 12:48 pm I'm loosing the original exposed aggregate appeal because of a few changes that have occurred, the sharpness of stones and the realization of the difficulty in maintaining it,...unless you have an extremely good OCD for exposed aggregate driveways. Sealing definitely and probably every couple of years for 6 and bleaching and high pressure washing before re sealing. That is if you are looking for a little extra 'look' and maintenance, alternatively you could just siloxane and live with the appearance. The siloxane will reduce dirt pick up, reduce moisture ingress(staining) and is not subject to abrasion or uv (Though can be high pressure washed and bleached and should not need resealing for 10 years) ~12$sq/mtr(it is a flood coat not a wipe over) Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 10Mar 16, 2015 1:14 pm Key joints have their place and purpose. I am not the engineer generic key joints are popular. Sometimes modifiers, additives and fibres are overlooked and control jointing in itself has limitations. Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 11Mar 16, 2015 2:52 pm I was only referring to the concrete apron I am placing around the house for slab protection and also a 5 meter long driveway for the Connelly key and not the engineered house slab if that makes any difference to your answer. Do you place a hand done joint above the keys if used? Re: Concrete advice - small cracks and dusty 12Mar 16, 2015 4:49 pm Where you are coming from is where you are going to... Re: Concrete advice - small cracks and dusty 14Mar 16, 2015 6:23 pm onc_artisan Well to me it looks like they used a lot of water to finish... but as I wasn't there and likely a number of reasons, but looking at the photos and the poor edge finish, I just don't think it was finished('closed off') sufficiently. Not enough cement 'drawn' to the surface. If it was hot and the case was, water was used, then a (x)% of cement was washed out of the top few mm resulting in deficient cement content. Was the concrete mix 20mpa? (20/20/80) Where the path is will be how you deal with it. If the aggression of the surface is good (textured) for slip resistance and the path is on the south side with minimal sun, moss will grow. Sodium hypo occasionally will help this. If you want to stop if from 'dusting off' then without creating a maintenance issue and sealing it with paint or other topical coating that will wear out and require more painting. You could acid etch it and this will release a lot of loose particles that 'abraid' off over time( called dust LOL) and should reduce dusting off considerably. Or remove and replace Thanks for your advice. I think I might seal it..will ask the concreter. I'm not too worried about cosmesis but certainly don't like imperfections!! Its on the side where no one goes .. Took a few more pics of cracks. And what are the cuts in the concrete exactly for ? Re: Concrete advice - small cracks and dusty 15Mar 16, 2015 6:50 pm That is pretty much my point. The mass of concrete causes shrinkage cracks if the (de)hydration is too rapid. ..they never go straight. That was a very wet batch of concrete... IMHO too wet Where you are coming from is where you are going to... Do I need to concern about this pattern of crack? Is this crack showing some signs of bigger problems? Thanks for any suggestions! 1 834 Last year I had a gas leak at my house. 3 days later, I have about 1 sqm of my exposed aggregate paving broken up. I am not sure how to go about getting it repaired… 0 8101 The spacing of the studs looks pretty large especially for a load bearing wall. 3 8157 |