Due to nearly constant internal and external conflict, Afghanistan’s infrastructure is in a constant state of disrepair and rebuilding. The country has limited network of paved roads, with the main artery Highway 1, circling the country. Nearly two thirds of the country’s population lives within 30 miles of the road (Sieff). Recently, the government of Afghanistan has shown an inability to maintain the roads, due mostly to inexperience and lack of funds. While some of the deterioration happens because of
If an aging pavement has become unsightly, check to see if it can be salvaged with an overlay before committing to a total replacement. If the foundation is stable, it might be cost-effective to choose an overlay, which is a course of asphalt applied to existing pavement.
First-time visitors to Lakeway are sometimes surprised to find that many streets and residential driveways are paved with asphalt. Unlike many other towns in the area, Lakeway was not founded in the 19th century. By the time Lakeway was planned, road builders had already begun to embrace asphalt pavement as the preferred choice. Asphalt pavement is economical, durable and attractive, and installation and repairs are quick and easy. At Alpha Paving, we offer a full range of asphalt services to the Lakeway area, including asphalt paving and overlays, sealcoating, crack filling, pothole repairs, street maintenance, asphalt milling and reclamation, pavement markings, speed bumps and parking lot striping.
Asphalt pavement is installed over a compacted foundation that supports the weight of the pavement as well as the traffic load. Anything that weakens the foundation also weakens the pavement. By far, the most common cause of a weakened foundation is water infiltration. Breaks
WHen it comes to susrface materials, asphalt is the number one choice as far as roads go. However, the same thing can't be said about driveways and sidewalks. As a matter of fact, have you ntocied that virtually every instances of sidewalk that you see within AUstraila, consist of concrete? This is due to the fact that concrete perfoms well under hot temperature and is an ideal surface material for driveways and walkways in general. In this post we'll take a look at the benefits that are associated with Conrete driveways.
However, it is weak in tension as the cement holding the aggregate in place can crack, allowing the structure to fail. Reinforced concrete solves these problems by adding either meta reinforcing bars, steel fibers, glass fiber, or plastic fiber to carry tensile loads.
Reinforced concrete is one of the most important available materials for construction in Egypt and all over the world. It is used in almost all structures as: buildings, shells, bridges, tunnels, tanks and retaining walls. Concrete is made by mixing binding materials as sand and gravel held together with a paste of cement and water. The used of admixture is to change certain characteristic of concrete such as workability, durability and time of hardening. Some of concrete advantages are its high compressive strength, its ability to cast in almost any desired shape, its economical and fire resistance. Low tensile strength, low ductility and cracking consider one of its disadvantages. Regardless of this disadvantages,
Abstract— Concrete is a composite construction material composed of aggregate, cement and water. There are
According to Tam (2002) concrete is a commonly used construction material in most parts of the world.There are many different types, strengths, and compositions of concrete and all of them have different characteristics that make them perform better for different applications. The following report is an outline of the different aspects of concrete itself. It includes the special concretes and their applications that are best suited for the construction of a shopping mall, the types of extenders that may be used together with the different admixtures.
Concrete is the second most utilized substance in the world after water and is the most widely used construction material with an annual global production of about 10 billion tonnes. It is preferred in most structures because of its unique properties such as durability and high compressive strength. It is however relatively weak in tension, its tensile strength being about 10-15 % of its compressive strength requiring that it be reinforced with materials such as steel rods, glass or plastic fibers in order to improve its ductility. It is also prone to slight shrinkage during the drying process and may lead to cracking especially in normal strength concretes. (R. I. Gilbert, 2001). As defined by the Portland Cement Association, the durability of concrete is its ability to counteract abrasion, weathering action and chemical attack, and still maintain its desired engineering properties. The proportioning and interactions between concrete ingredients, placement and curing practices as well as the service environment determine this ultimate durability and life. The ideal situation therefore in any construction project is to choose the correct concrete type which will be more durable based on the project requirements.
Continuously reinforced concrete pavements (CRCP) was first designed 100 years ago when the Federal Highway Administration constructed a CRCP testing section. CRCP is now being used in numerous states around the United States and even around the world. CRCP has proven to be such a useful design. With the design and construction growing, there has been many lessons learned through its use and research. Which has contributed to better practices and a longer life cycle, making its ability to maintain a “zero-maintenance” service life through harsh environmental conditions and heavy traffic loadings. As long as proper design and construction is being utilized (as shown in figure 1) the design should need only minimal
For this widening road project, individual and careful planning is needed for well systematic schedule, minimal costs and safety of the work. The site layout, sequence of activities and materials that are needed are vital points to include when planning earthworks and is affected to a large extent of the project. Site investigation is needed for the earthworks to be carried out on the freeway by examining the original and the final arrangement
The strength of concrete used in the design is 40 MPa for Piles, and 60 MPa for Pile Caps, Columns, Towers, and Girders. In addition, Micro silica is added to increase concrete strength as well as providing sulfate resistance by decreasing average size of pores in the cement paste.
These mega road modernization exposes challenges of various concerns pertaining to depletion of resources like good soil and aggregates, long lead to get good quality aggregates and increase in fuel consumption etc,.
The properties of aggregates used in asphalt concretes are very important to the performance of the pavements in which the asphalt concretes are used. Often pavement distress, such as stripping and rutting, can be traced directly to the aggregates used. Clearly, proper aggregate selection is necessary for attaining desired performance. The aggregate used in surface course of the highway pavements are subjected to wearing due to movement of traffic. When vehicles move on the road, the soil particles present between the pneumatic tyres and road surface cause abrasion of road aggregates. The steel reamed wheels of animal driven vehicles also cause considerable abrasion of the road surface. Therefore, the road aggregates