It is thoroughly moistened so that it does not absorb water from the concrete. It also allows easy sliding of the concrete slab on top of the layer. Sometimes, special waterproof paper is used instead of a layer of sand as insulation material. This paper prevents any absorption of water by the subsoil or the subfloor.
Concrete roads are manufactured with a concrete mix of Portland cement, coarse-grained aggregates, sand and water. The most important advantage of a concrete road is its useful life due to its exceptional durability. They are considerably less prone to wear defects such as grooves, cracks, stripping, loss of texture and potholes that can occur with flexible pavement surfaces. This low maintenance requirement is one of the main advantages of concrete pavements.
There are well-designed concrete pavements that have required little or no maintenance. Less maintenance also means fewer traffic delays, a big advantage on some of our already congested roads. After 24 hours, the form job moves to the next stretch of road. Typically, three basic types of joints are used in concrete pavement, ranging from shrinkage, construction, and insulation.
In addition, insulation joints, all joints are arranged to tie slabs mechanically. The connection facilitates the dispersion of a forced load on a slab onto the slabs along its perimeter, To organize transverse and longitudinal joints, wooden wedges, metals must be fixed at the concrete level. Once the concrete has set, it must be removed, Mixture of material & set from concreteConcrete is mixed through a mixer with cement, concrete, sand and water. The following types of mixers are normally applied throughout construction, batch mixer? Suitable for small road construction Continuous mixer? Suitable for large construction If the distance is long from the job site, the concrete mix is transmitted to the site within the setting time.
In this method, the construction of the cement concrete pavement is carried out in alternate bays; the bays remaining in the first instance are made after the concrete already laid is properly hardened: one week for ordinary Portland cement and two to three days for fast-hardening cement. Continuously Reinforced Concrete Pavement (CRCP): Continuous Reinforced Concrete Pavement (CRCP) contains continuous, longitudinal steel reinforcement without transverse joints, except where necessary for head joints at the end of the day, bridge approaches and transitions to other pavement structures. Typically, three basic types of joints are used in concrete pavement, ranging from shrinkage, construction and insulation. Each of the above machines used in the construction of cement and concrete roads will now be described shortly.
It will be interesting to summarize the two important types of advertising surfaces in common use, namely flexible pavement in the form of bituminous concrete roads and rigid pavement in the form of cement concrete roads. After use, the concrete mixer must be thoroughly washed and cleaned. If this precaution is not taken, hardened concrete cakes will form inside the mixer. Equipment needed for concrete road construction ranges from large plants and machinery to small pieces of equipment for batching, mixing, laying, finishing, surface texturing, curing and quality control.
To do a good job, open concrete can be extended, assembled and finished with a rotating plant that moves slowly over the forms on the metal side that is used as the side closure of the concrete. There has been considerable improvement in joint technology on concrete roads and therefore most modern concrete roads are built with this method. Articulated Reinforced Concrete Pavement (JRCP): Jointed Reinforced Concrete Pavements (JRCP) contain steel mesh reinforcement (sometimes called distributed steel). The gyratory plant allows the use of a strong concrete mix and the concrete mix is also better than when done by hand.
Cement-concrete roads are in the form of monolithic cement-concrete slabs that serve two functions simultaneously, namely as a load base and as a wear surface. In new concrete pavements, volumetric changes caused by cement hydration, thermal effects and external drying are restricted by the pavement base layer and longitudinal reinforcement, causing tensile stresses to develop in the concrete. This construction is specifically used for concrete road pavements and airport runway pavements, since it can withstand heavy loads. The material can be granular, bituminous or cement concrete, depending on the nature of the construction.
Smooth articulated concrete pavement (JPCP): Smooth articulated concrete pavement uses shrinkage joints to control cracking and does not use any reinforcing steel. It is essential that the shapes are checked before placing the concrete, since the alignment of the concrete slab depends on them. . .
