2.2.2.2 MOBILE CONCRETE BLOCK MACHINE
The mobile concrete block machine operates on a solid reinforced concrete platform. The hopper in the machine receives concrete by a forklift, the concrete is then pressed using vibration and hydraulic force between mould and the concrete floor, forming the shape of concrete block. The blocks are left to cure naturally (some times they might be covered using a plastic sheet) once cured, they are collected using forklifts, and stored in a yard till sold.
2.2.2.3 USES
Concrete block, when built in tendem with concrete columns and tie Beams and reinforced with rebar, is a very common building material for the load-bearing walls of buildings, in what is termed “concrete block structureâ€( CBS) construction. American suburban house typically employ a concrete foundation vibrant and slab with a concrete block Wall on the perimeter. Large buildings typically use copious amounts of concrete block; for even larger buildings, concrete blocks supplements steel I-beams. Tilt-wall as well as steel frame construction is both to Some extent replacing CBS for. some larger structures, particularly those more than seven stories.
2.2.3 CEMENT
Cement is often supplied as a powder, which is mixed with other Materials and water. Many types of cement powder can cause allergic reactions upon skin contact and are irritating to skin, eyes, and lungs. So handlers should wear a dust mask, goggles, and protective gloves, unlike the worker pictured here.
Cement is a binder, a substance used in construction that sets and Hardens and can bind other materials together. The most important
Types of cement are used as a component in the production of mortar In masonry and of concrete, which is a combination of cement and an aggregate to form a strong building material.
Cement used in construction can be characterized as being either Hydraulic or non- hydraulic, depending upon the ability of the cement To set in the presence of water.
22.3.1 MODERN CEMENTS
Modern hydraulic cements began to be developed from the start of the industrial Revolution(around 1800), driven by three main needs:
. Hydraulic cement render (stucco) for finishing brick buildings in wet Climate.
• Hydraulic mortars for masonry construction of harbor works e.t.c in contact with sea water.
• Developed of strong concretes
Modern cements are often Portland cement or Portland cement blends, But other cements are used in industry.
22.3.2 PORTLAND CEMENT
Portland cement is by far the most common type of cement in general use around the world. This cement is made by heating limestone ( calcium carbonate) with other materials ( such as clay) to 1440c in a kiln, in a process known as calculation; whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or quicklime, which is then blended with the other materials that have been included in the mix to form calcium silicates and other cementation compounds. The resulting hard substance, called “clinker†is then ground with a small amount of gypsum into a powder to make ordinary Portland cement, the most commonly used type of cement ( often referred to as OPC), Portland cement is a basic ingredient of concrete, mortar and most non-specialty grout. The most common use far Portland cement is in the production of concrete. “Concrete is a composite material consisting of aggregate, gravel and sand, cement, and water. As a construction material, concrete can be cast in almost any shape desired, and once hardened, can become a structural (load bearing) element. Portland cement may be grey or white.
