When you're laying down a new concrete driveway, concrete floor or concrete parking lot, you may want to consider the use of exposed aggregate. This is decorative material such as coloured stones, granite, quartz and limestone, that is mixed in with standard concrete to create a surface that has visual appeal, and can also prolong the life of your concrete. If you don't know much about aggregate concrete, here are the three ways that aggregate is added to concrete.
Direct Mix -- The first method that concrete contractors will use to add aggregate to concrete is to directly mix the aggregate into freshly mixed concrete that hasn't dried. This is much easier than trying to 'seed' the aggregate after the concrete has been poured out, but one thing to remember is that if you have chosen expensive aggregate, you will need to buy a larger quantity than if you were seeding after the concrete has set. Seeding aggregate on poured concrete requires less aggregate because this method is more about sprinkling the aggregate than mixing it into batched concrete.
Seeding -- When concrete contractors talk about 'seeding,' they are referring to the process by which they add aggregate to concrete that has already been poured and is setting prior to hardening and curing. To seed aggregate, a concrete contractor will gather the aggregate by hand and literally sprinkle or shake it out over the surface, 'seeding' it with the aggregate. In some instances in which the surface is very large, the contractor will use a shovel to seed the aggregate. Once the seeding is completed, the contractor will use a tool known as a 'bull float,' which has a long handle with a thin, rectangular end made out of wood or steel that helps implant the aggregate into the wet concrete. A bull float is ideal because it doesn't seal the surface, and allows excess water to drain from the concrete.
Thinning -- A third method by which a concrete contractor can add aggregate to concrete is through thinning. This is a process in which a thin layer of mixed concrete and aggregate is applied to a concrete base, concrete slab or concrete foundation. This thin layer is then allowed to dry over the base, slab or foundation, creating the exposed aggregate look. Thinning is typically used only when you're adding a very small amount of aggregate, because the thinness of the aggregate and concrete layer is such that it can't support a large amount of aggregate.
For more information, check out companies such as Dromana Concrete Products.
Share19 February 2015
Concrete may seem boring to the uninitiated, but as the wife of a concrete contractor, I have learned, over the years, that it is anything but boring. Contemporary concrete can be used in a range of applications from functional sound walls to decorative koi ponds, and it can be left gray, stamped or acid stained. If you are getting ready to do a project, you have come to the right place. In this blog, I am going to post a myriad of information about concrete with an emphasis on project ideas and the different uses of concrete. By the end, I hope you find concrete as exciting as I do!
