The do's and doníts when pouring stamped concrete roadways.....
Stamped concrete is used to give a special appearance to concrete other than your average broom or smooth finish's. Stamped concrete when placed correctly can be very durable and long lasting for roadways. And can help with certain themes or historic areas youíre trying to match or work with. There are many things to think about before you start a concrete roadway project. First would be what kind of traffic are you going to have on your roadway. Heavy, mid or light weight traffic and the volume of traffic. Stop lights, side roads, entrances both residential and commercial are other key factors in the designing and planning you project. Your concrete mix design all depends on the stamped concrete pattern youíre using. If you are using a pattern with deep texture or grout lines. It is better to use a mix with smaller stone; this gives a more detailed edge to your pattern. Less aggressive patterns you should use larger stone. Itís always a good idea to use reinforcing fiber in your stamped concrete mix design. Nylon fiber works best in stamped concrete. Nylon will not float or work its way to the top of your concrete when you are floating and screeding. Fiber glass fiber tends to float and ball up on the top of your concrete while you are floating and prepping forms your stamp process.
Planning your pour is the most important part of a stamped concrete roadway. No more than 400 s.f. should be poured at one time in a set pour. This may vary 40 to 60 s.f. + or - depending on temp, humidity and direct sunlight. But on the average in our area here in east TN 400 s.f. is a good rule of thumb to go by. Timing is key to the durability and lasting of your stamped concrete. After placing your concrete in your forms there is no set time to start your stamping procedure. If you start your stamping to soon the quality of the stamp work is hard to maintain. When the concrete is to wet it will pump and cause an uneven surface. When you wait to long on the concrete to stamp, you are directly affecting the integrity of the concrete. Waiting to late on the concrete will cause surface scaling almost every time. Basically when you wait to long your trying to beat or hammer the pattern into the concrete. Which will separate your cement from the stone in your concrete. This will cause surface scaling. If you have a 400 s.f. area to stamp the best way to think about it, is the whole area needs to stamped at the same time when the concrete is ready. That is where speed and experience comes into play. A good team and a pre pour plan goes a long way.
Control joints are another key part to long lasting concrete work. Control joints should be planed out before placing the concrete. When planning your control joints think of ways to discise your joints in the pattern youíre using. Expansion joints should be used any time you pour in a place that your concrete has no room for expansion. For example, if you are pour a 5' sidewalk with curb on one side and grass area or landscape on the other side then you would not need expansion on the curb side. Your grassy area or mulch landscape area will let your concrete expand with no damage to curb or your concrete sidewalk. An example of when you would need expansion, if you were pouring a 5' sidewalk with a curb on one side and solid structure on the other side like a masonry wall. You would want your expansion on the high side of the cross section of your sidewalk. Witch would be the masonry wall side. Expansion in concrete roadways can be figured by the thickness and length of your roadway.expastion material or smooth dowels will work fine when used correctly. All of your control and expansion joints should be seal with the proper sealer. The sooner the better.
Weather is always important when planning your concrete pour. High winds and low humidity are silent killers of concrete. Both will cause rapid curing. This will cause stress and surface cracks. Wind can also cause surface scaling. There are no curing compounds you can use on stamped concrete. Sealing your stamped concrete after washing the day after you pour will help with your longer curing time. Plan your stamped concrete pours with the weather. Coloring stamped concrete can be done several ways. Intragal color is the best way to get a uniformed mix and color. Cast on or color hardeners can be used but can be hard to keep uniformed color. Acid staining can be used to color your stamped concrete as well. Acid staining is used more in marbling or antiquing stamped concrete.
Spend time to plan your stamped concrete projects from start to finish and the finished product will always turn out better
BP&G concrete consulting. Sam Snyder
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