The Highways Agency Manual of contract documents for highway works requires the surface macro-texture to be measured using the volumetric patch technique described in BS EN 13036-1.īrushed finishes are relatively shallow and may quickly wear away under service traffic. The National Building Specification requires a brushed finish to produce a “lightly textured surface”. Therefore it must be appreciated that the aesthetic appearance of a brushed finish on large areas may be disappointing. Do not spray directly at the slab surface or finish the water into the slab. Many of the above comments on the difficulty of obtaining a uniform finish apply particularly to brush finishes. Hand or mechanical brush finish usually gives striations which are 1.5–3mm deep. Its disadvantage is that it is difficult to control the frequency of the striations and the profile of the texture. Brushing transverse to the direction of the traffic either by hand or machine using a stiff brush has been used widely. If it is used too early bleed water can be worked into the surface, thus weakening it, and pieces of coarse aggregate may be ‘plucked’ out of the surface by the brush.īrushed finishes are suitable for areas trafficked either by vehicular or foot traffic and are also suitable for many types of mechanical handling plant. Care is needed with the timing of the use of this equipment. The brush is then drawn back across the bay. The photo was taken at the time of application of the broom finish while the. When the skip float has reached the bay edge the handle is turned which lifts the skip float and lowers the brush head onto the concrete. A photo follows below of a cast in place concrete slab, installed in Washington DC. In use, the skip float is pushed across the bay using the long handle. Such brushes generally have steel bristles or tines and long heads to reduce the number of passes.Ī commonly used piece of equipment for producing a brush finish is the combined skip float and brush. Normal manual sweeping brooms produce an unsatisfactory texture for finishing concrete surfaces and should not be used rather, a purpose-made brush should be used. Brushes can have plastic bristles or steel tines of varying gauge and density. Coarse texture is given by stiff-bristled brooms, softer bristles giving medium and light textures. The type of finish obtained will depend upon the coarseness of the brush bristles and the length and shape of the tufts. The surface is comfortable to walk on while still offering excellent traction, and the unobtrusive finish is suitable for any style of landscape.A brushed finish is obtained by pulling a brush over the surface of the fresh concrete, after the surface has been levelled. When the top layer of cement is washed off, the concrete is left with a uniform texture much like the surface of sandpaper. For a sandwash finish, the mix will have a higher proportion of small sand-sized particles versus pebble-sized particles for exposed aggregate. Sandwashed concrete undergoes a similar finishing process as exposed aggregate, but the composition of the concrete mix is different. Exposed aggregate is also prone to damage, as the protective cement that binds the aggregate together has been removed from the surface of the concrete. The aggregate, however, often has sharp or pointy edges which can dig into bare feet, making it an uncomfortable choice for a backyard patio. Exposed aggregate concrete features a bumpy, pebbled texture, which creates excellent traction when wet. That outer layer is then washed off, revealing the aggregate within the concrete. To give concrete an exposed aggregate finish, the surface of the wet concrete is treated with a chemical that stops the outer layer of cement from curing. For a little extra interest, a colored pigment can be mixed into the concrete to give it a tone other than the basic gray. As you are about to find out, this is an easy process and there aren’t many steps involved at all. Its popularity lies in the fact that it is a durable and economical finish, as well as one that provides good traction in wet conditions. Now that you know the basics of doing a broom finish on concrete, let’s go through a step-by-step tutorial on exactly how to get it done. It is commonly used for sidewalks and driveways and, as the name suggests, involves dragging a broom across the surface of the wet concrete to give it a ridged texture. A gray, broom-textured concrete is the most basic outdoor concrete finish.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |