The Lancaster Turnpike The first engineered and planned road in the United States was the Lancaster Turnpike, a privately constructed toll road built between 1793 and 1795. Connecting Philadelphia and Lancaster in Pennsylvania, its 62-mile length had a maximum grade of 7 percent and was surfaced with broken stone and gravel in a manner initially uninfluenced by the…
In RC buildings, portions of columns that are common to beams at their intersections are called beam-column joints (Figure 1). Since their constituent materials have limited strengths, the joints have limited force carrying capacity. When forces larger than these are applied during earthquakes, joints are severely damaged. Repairing damaged joints is difficult, and so damage…
A true flexible pavement yields “elastically” to traffic loading. It is constructed with a bituminous-treated surface or a relatively thin surface of hot-mix asphalt (HMA) over one or more unbound base courses resting on a subgrade. Group Index method of flexible pavement design is an empirical method which is based on the physical properties of…
Air entrained concrete A major advance in concrete technology in recent years is the introduction of tiny disconnected air bubbles into concrete called air entrainment. Air entrained concrete results from using either an air-entraining cement or an air-entraining admixture during mixing. Adding entrained air to concrete provides important benefits in both plastic and hardened concrete,…
Carbonation is the result of the interaction of carbon dioxide gas in the atmosphere with the alkaline hydroxides in the concrete. Like many other gases carbon dioxide dissolves in water to form an acid. Unlike most other acids the carbonic acid does not attack the cement paste, but just neutralizes the alkalinity in the pore…
A tall building like the “Burj” in Dubai is almost 818 meters (2684 feet) above the ground level, which is currently the world’s tallest man-made structure. But how can you calculate it’s height? There are actually several methods of doing so without leaving the ground. Everyone is aware of the Empire State building or the Eiffel Tower….
Reservoir, an open-air storage area (usually formed by masonry or earthwork) where water is collected and kept in quantity so that it may be drawn off for use. reservoir Changes in weather cause the natural flow of streams and rivers to vary greatly with time. Periods of excess flows and valley flooding may alternate with low flows or droughts….
Concrete reinforcement technology is not new and fibers have been used for reinforcement since ancient times. Popular fibers are made up of steel and glass, while plastic and nylons have a limited use. Quantities, concentration, and dispersal influence the properties of fiber reinforced concrete What Is Fiber Reinforced Concrete Fiber reinforced concrete is a type of concrete that includes fibrous substances that increase its…
Plain concrete, commonly known as concrete, is an intimate mixture of binding material, fine aggregate, coarse aggregate and water. This can be easily moulded to desired shape and size before it looses plasticity and hardens. Plain concrete is strong in compression but very weak in tension. The tensile property is introduced in concrete by inducting different materials…
Concrete block masonry which is also known as concrete masonry unit (CMU) have advantages over brick and stone masonry. Concrete blocks are manufactured in required shape and sizes and these may be solid or hollow blocks. The common size of concrete blocks is 39cm x 19cm x (30cm or 20 cm or 10cm) or 2…