NOISE PROTECTION PRINCIPLES OF HIGHWAY CONSTRUCTION

Abstract

One of the most effective means of combating the noise load from the highway is the installation of noise protection screens along the highway. They can be made of different materials, different in design and geometric parameters. Plexiglas sound-proof screens have become quite widespread on highways. Plexiglas is an environmentally friendly product based on polymethyl methacrylate. Its other name is acrylic, and it belongs to a type of artificial organic plastics. The basis of the material is thermoplastic acrylic resins, more precisely, one or more derivatives of a monobasic carboxylic acid. These are components that transmit light well. The chemical formula of acrylic is the same as that of plexiglass - (C5O2H8) n, but in addition, its composition includes many additives that add special properties to the thermoplastic structure, such as hardness, flexibility, resistance to mechanical loads and damage, as well as pigments necessary to obtain a specific color [1]. Currently, there are two types of material. Plexiglas XT - this product is made using an extruder. Under pressure, methyl methacrylate passes through the forming tool of the equipment, and products are obtained from the melt in the form of solid panels with a thickness of no more than 25 mm, as well as rods, rounded profiles, sheets with a wavy and reflective surface. Such plastic has increased elasticity and flexibility, it is easier to transform it into various forms, but at high temperature it gives a small estate, and its strength leaves much to be desired. Cast acrylic glass Plexiglas GS, obtained by polymerization at the stage of forming a blank from acrylic under the influence of an activator, is considered stronger. During this chemical process, the glass molecules line up in strong long chains, and thus the maximum strength of the product is achieved. Its common forms are pipes, blocks of different thicknesses, monolithic sheets that are resistant to deformation and aggressive environments. But the flexibility of this type is much lower than that of the extrusion version. In general, acrylic glass has increased impact strength, which is 5 times higher than that of ordinary glass. [1] The excellent characteristics of the product are due to its physical properties: ● insensitivity to sunlight, lack of color changes and desire; ● strength is higher than that of quartz glass; ● high light transmission and the ability to store heat due to low thermal conductivity; ● resistance to microorganisms, aggressive chemistry, large temperature range, moisture; ● lightness compared to ordinary glass with a minimum layer of 1 mm (the weight of 1 sq. m is only 1.2 kg); ● when burning, Plexiglas products do not emit harmful fumes, and the material does not form dangerous sharp fragments when damaged; ● the polymer is easy to cut and give it any necessary shape; ● the material is hygienic, does not require complex care, due to the fact that its surface is smooth, and dirt and dust particles do not accumulate on it. At the same time, this wonderful synthetic material has several disadvantages: products made of it are prone to external damage, and also catch fire easily