I’m going to be putting in a walkway to the driveway and sidewalk. It is going to abut the existing old concrete drive way and the newer sidewalk.
Typical front walkway in size with the whole thing curved around the landscaping.
I’m going to keep it concrete in color but am thinking about finishes.
I’ve seen where they come in after a few days and sandblast it to give it an aged look. I think it just exposes the sand.
Is there a way I could do it with a pressure washer?
Replies
You can do an exposed aggregate and get a similar look with the pressure washer, or a hose. There are a variety of ways of doing this but the basic idea is you wash the cream off the top after it has started to cure. The typical method is to use retarder on the surface, let cure overnight and wash. The timing, and the retarder, or lack of retarder you use will alloy you to achieve everything from very a very rough aggregate look to just exposing the fine aggregate/sand some.
Off the top of my head for the look I think you are going for I would use a 3/8"/pea gravel mix, a light coat of a light etch retarder, cure 24 hrs. and wash.
Rob
Thank you! I'm getting excited. I was going to use pea gravel. The last flat work pour I did was 3/4" and I just don't like dealing with the larger rock.
I'll be more careful specifying the mix this time. I was also thinking of throwing on some rock salt in places. Just to soften up the look a bit.
I'm not sure of the name. In plastering they have a name for the areas that aren't smooth and are recessed a bit. Are they called highlights? Anyway, I was thinking of randomly throwing some rock salt on in patches like highlights in plaster.
Along with the washing it should look good.
I have to find a concrete supply yard that will sell me the product and talk me through it a bit. I've been to the White Cap here but didn't like them. I might have to go back anyway. I miss my old yard. They always set me up right.
Edited 5/23/2008 2:52 pm ET by popawheelie
you can let it set slightly, spread sugar on top and it will keep itfrom setting then wash off next day with water
Sweeet!
how's the sugar work?
it retards the cement from setting up
...yeah I know that, from your post... but HOW does it work?
Chemically?
Yes , chemicalSugar is an acid, concrete is a base. I was taught this years ago , I never questioned it but it is incorrect apparently. See peteshlagor's post below. See post 104900.16 How it works I now do not know but it does work.
Edited 5/24/2008 9:30 am by dovetail97128
Say, Dovey, can you provide me a good chemical explanation to support your claim that sugar is an acid?
"Chemistry
View Image
Sucrose: a disaccharide of glucose (left) and fructose (right), important molecules in the body.
Biochemists regard sugars as relatively simple carbohydrates. Sugars include monosaccharides, disaccharides, trisaccharides and the oligosaccharides - containing 1, 2, 3, and 4 or more monosaccharide units respectively. Sugars contain either aldehyde groups (-CHO) or ketone groups (C=O), where there are carbon-oxygen double bonds, making the sugars reactive. Most simple sugars (monosaccharides) conform to (CH2O)n where n is between 3 and 7. A notable exception, deoxyribose, as its name suggests, has a "missing" oxygen atom. All saccharides with more than one ring in their structure result from two or more monosaccharides joined by glycosidic bonds with the resultant loss of a molecule of water (H2O) per bond.
As well as using classifications based on their reactive group, chemists may also subdivide sugars according to the number of carbons they contain. Derivatives of trioses (C3H6O3) are intermediates in glycolysis. Pentoses (5-carbon sugars) include ribose and deoxyribose, which form part of nucleic acids. Ribose also forms a component of several chemicals that have importance in the metabolic process, including NADH and ATP. Hexoses (6-carbon sugars) include glucose, a universal substrate for the production of energy in the form of ATP. Through photosynthesis plants produce glucose, which has the formula C6H12O6, and then convert it for storage as an energy reserve in the form of other carbohydrates such as starch, or (as in cane and beet) as sucrose (table sugar). Sucrose has the chemical formula C12H22O11.
Many pentoses and hexoses can form ring structures. In these closed-chain forms, the aldehyde or ketone group remains unfree, so many of the reactions typical of these groups cannot occur. Glucose in solution exists mostly in the ring form at equilibrium, with less than 0.1% of the molecules in the open-chain form.
Monosaccharides in a closed-chain form can form glycosidic bonds with other monosaccharides, creating disaccharides (such as sucrose) and polysaccharides (such as starch). Enzymes must hydrolyse or otherwise break these glycosidic bonds before such compounds become metabolised. After digestion and absorption. the principal monosaccharides present in the blood and internal tissues include glucose, fructose, and galactose.
The prefix "glyco-" indicates the presence of a sugar in an otherwise non-carbohydrate substance. Note for example glycoproteins, proteins connected to one or more sugars.
Monosaccharides include fructose, glucose, galactose and mannose. Disaccharides occur most commonly as sucrose (cane or beet sugar - made from one glucose and one fructose), lactose (milk sugar - made from one glucose and one galactose) and maltose (made of two glucoses). These disaccharides have the formula C12H22O11.
Hydrolysis can convert sucrose into a syrup of fructose and glucose, producing invert sugar. This resulting syrup, sweeter than the original sucrose,[20] has uses in making confections because it does not crystallize as easily and thus produces a smoother finished product.
If combined with fine ash, sugar will burn with a blue flame."
I never knew about this concrete reaction until this thread. But I do know that a base and an acid combined results in water and a salt. Reading thru 4 or 5 pages of the Google results only tells me that the sugar "coats" the ceement particles. Nothing is mentioned about an acid-base reaction.
I did find something about a "concrete dissolver" based upon the waste of sugar refining. But nothing about the specifics.
There's something else involved here other than acids and bases...
Uh , NOPE! I never questioned what I was told years ago by the guys who put a seminar on at the local batch plant on how to create an exposed aggregate finish.
Guess I am guilty of passing on incorrect information. Their explanation made sense given one of the only things I know about chemistry is the reactions between base and acids in terms of one neutralizing the other. Thanks for the correction. I will edit my post.
They can't get your Goat if you don't tell them where it is hidden.
Oh they neutralize all right. But leave other things behind.
I gotta admit, it's been 35 to 40 years since I studied something in this area. We gotta call in the big guns.
NUKE!? Where's your wife?
What's the chemistry really involved here? I don't question that it works, but how? They're mixing organics and inorganics. Why would that work better over using simple muriatic acid? Why is it specific for the ceement, but nothing else?
Only in the presence of a strong base would a sugar molecule act as an acid. An acid is something that donates protons (Hydrogen ions). The OH components in sugar would release the Hydrogen ion to the base, whereas acting as a very weak acid.
At least, that is what she said. :)
Thanks.
Therefore, I'm claiming this phenomen is not acid / base in foundation. Otherwise, stronger acids and other weak acids would display greater / similar effect.
Is it magic? Or this aforementioned "coating" effect inhibiting the ceement bond from forming?
Nuke, The remaining -O or =O after the release of the proton is also reactive, perhaps more so. Therefore something else would be created. Perhaps this subsequent product has an involvement?
Rock salt will damage the concrete and make it susceptible to spalling. I'd stay away from the salt. Use quartz or other solid rock instead of salt.
I did a pour ( not very well) that was a rock salt finish a long time ago. You spread the rock salt on top and push it into the finish. The next day you wash it out. It dissolves so It can come out.
Would the quartz wash out? I'm not saying the salt is the only way to go. I'm just looking for some way to ge a look like the concrete isn't brand new and has some character.
With quartz, could I just leave it in? Just push it the whole way and leave it there?
If you decide to go with exposed aggregate, you might want to find a friend who has some experience. I don't think I've ever seen a first attempt that has turned out well. It is very easy to let it get away from you and have an inconsistent finish.
You should also check with your municipality. Most areas are rather picky about washing all that cream into their storm sewers or ditches.
Exposed aggregate looks great when it's first down, but unless you regularly re-seal it soon looks like any other old concrete.
I agree. If it isn't done well it could look like any old concrete. I suppose that is true of most things.
If it looks like "any other old concrete" at least it won't look like brand new broomed concrete. That's what I'm trying to stay away from.
That and over done/worked concrete that looks stupid imo.
I'd like it to look like a good job that has been there for a while.
To the trained eye it will tell. But to most it will look nice and natural.
At least that's what I'm shooting for.
"That and over done/worked concrete that looks stupid imo. I'd like it to look like a good job that has been there for a while"
I stupidly posted all the negatives about exposed aggregate, without saying that I think it is a good choice. I just find concrete finishing nerve-wracking.
There certainly is something unsettling about a house surrounded by a sea of "showcase" concrete that makes it look like a brochure for the product.
I agree it is nerve wracking. If I have good help it is considerably less so. The last time I poured a slab it was using teens from the church youth group. That was nerve wracking. None of them knew how to work or place/finish concrete and one kid was belligerent with me the whole time. If I didn't need them I would have told them to go home. But I was stuck with them.
I feel your pain. The last couple of pours I did with inexperienced but enthusiastic help, I ended up doing all the wheeling. There is something about concrete in a wheel barrow that confounds even the biggest first timers. After a few yards of that, getting to the finishing was a relief.
I like how the help will show up in $200 tennis shoe, refuse to get in the mud and stand around all day drinking your beer. no boots, no shovels, no trowels. I end up doing all the work anyway
For a couple of years I built with a guy who just wouldn't learn to crib forms so that they didn't blow out. I got so that I would feel anxious every time I heard a concrete truck- whether it was for my job or not.
I will give you one hard earned tip. Do not use knee boards on the concrete if you are going to expose the aggregate. The weight will depress the gravel and can leave you a discernible mark from the boards after the top slurry is washed off.
Finish it using careful screeding, bullfloating and "Fresno" steel trowel on the bull float handles to remove any ridges.
They can't get your Goat if you don't tell them where it is hidden.
On small stuff when replacing part of existing I would sometimes wash the surface off with a sponge after it's set up a bit, so the patch closer matches the existing. Not sure how or if that applies to your project, but I like typing.
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