Apple chemie

Levelling (or Leveling) is a branch of surveying, the object of which is: i)                    To find the elevations of given points with respect to a given or assumed datum, and ii)                  To establish points at a given or assumed datum. The first operation is required to enable the works to be designed while the second operation is required in the setting out of all kinds of engineering works. Levelling deals with measurements in a vertical plane. ·          Level surface: A level surface is defined as a curved surface which at each point is perpendicular to the direction of gravity at the point. The surface of a still water is a truly level surface. Any surface parallel to the mean spheroidal surface of the earth is, therefore, a level surface. ·          Level line: A level line is a line lying in a level surface. It is, therefore, normal to the plumb line at all points. ·          Horizontal plane: Horizontal plane through a point is a plane tangenti

The process which involves the introduction of tiny air bubbles into concrete is called air entrainment. And the concrete formed through this process is called air entrained concrete. Using air entraining Portland cement or air entraining agents such as admixture, air entrainment is done in concrete. The amount of air in such concrete is usually between four to seven percent of the volume of concrete. It is measured by galvanometric method, volumetric method and pressure method. The air bubbles relieve internal pressure on the concrete by providing chambers for water to expand when it freezes. Process Here are the ways of incorporating air in concrete: ·          Using gas forming materials as aluminium powder, zinc powder and hydrogen peroxide. ·          Using surface active agents that reduces surface tension. They may be natural wood resins and their soaps, animal or vegetable fats or oils, alkali salts of sulfonated or sulphated organic compounds. ·          Using c

Curing is the process where the concrete surfaces are kept wet for a certain period after placing of concrete so as to promote the hardening of cement. It consists of a control of temperature and of the moisture movement from and into the concrete. Purposes of curing of concrete Following are the objects or purposes of the curing of concrete: 1.       Curing protects the concrete surfaces from sun and wind. 2.       The presence of water is essential to cause the chemical action which accompanies the setting of concrete. Normally, there is an adequate quantity of water at the time of mixing to cause the hardening of concrete. But it is necessary to retain water until the concrete has fully hardened. 3.       The strength of concrete gradually increases with age, if curing is efficient. This increase in strength is sudden and rapid in early stages and it continues slowly for an indefinite period. 4.       By proper curing, the durability and impermeability of concrete

  Regardless of the industry, all types of rock drills have a standard design that is essentially a combination of replaceable attachments. The most significant parts of a standard rock drill include the following: ·          Drill bit : This is the tip of the rock drill that first makes contact with the ground during a boring operation. ·          Drill stem : This is the long frame that penetrates the ground during boring whose end houses the drill bit. ·          Drill rod : This is the hollow part of the drill stem that connects the motor of the rig to the drill bit. The drill rod is also responsible for transferring the cutting force to the drill bit to enable the rock drill to penetrate into the ground. ·          Carbide bits : These are special types of drill bits used in rotary and percussive drilling that have carbide tungsten coated onto them at an angle. How Rock Drills Work During soil nailing, micropile, mining or tunneling operations, rock drills pene

Ready-mix concrete (RMC) is a type of concrete which is manufactured in a cement factory, or specifically known as the batching plant, according to a given set of proportions, and then delivered to a work site, by truck mounted with mixers. This results in a precise mixture, allowing specialty concrete mixtures to be developed and implemented on construction sites. The fist factory which produced ready mix concrete was built in 1930s; however, the industry didn’t begin to expand until late 80s. Since then it has continued to grow significantly. Ready mix concrete is sometimes preferred over on-site concrete mixing because of the volume it can produce with precision of proportion of mixtures and also due to reduced work site confusion. Using a pre-determined concrete mixture reduces flexibility, both in the supply chain and in the actual components of the concrete. Ready-mix concrete is also termed as the customized concrete products for commercial purpose. Ready-mix concrete

There are different types of bricks available on the market used for various kinds of purposes. These bricks can be categorized under various headings and subheadings on different basis. The various classifications of types of bricks are briefly discussed below. Classification based on method of manufacturing Bricks can broadly be categorized into two types as follows on the basis of how its manufactured: ·          Unburnt or sun-dried bricks ·          Burnt bricks o    Unburnt bricks Unburnt bricks or sun-dried bricks are the types which are dried with the help of heat received from sun after the process of moulding. These bricks can only be used in the construction of temporary and cheap structures. Such bricks should not be used at places exposed to heavy rains. o    Burnt Bricks Burnt bricks are prepared by burning the brick-mould in the kiln inside the factory. These are the most commonly used bricks for construction works. They can be further classifi

The following are important building stone, their composition, properties and uses: 1. Granite: It is an igneous rock. It is mainly composed of quartz, felspar and mica. Its specific gravity is 2.64 and compressive strength varies from 70 to 130 MN/m2. Its color depends upon that of felspar which may be brown, grey, green and pink. A fine-grained granite offers high resistance to weathering. It can be easily polished and worked. It is used for exterior facing of buildings. 2. Slate: It is an argillaceous rock. It is mainly composed of alumina mixed with sand or carbonate of lime. Its specific gravity is 2.8 and compressive strength varies from 60 to 70 MN/m2. It has grey or dark blue color. A good slate is hard, tough and fine grained. It is suitable for use in cistern. The slate in the form of tiles is used as an excellent roof covering material. 3. Gneiss: It is a siliceous rock. It is mainly composed of quartz and felspar. It is more easily worked than granite.

1. HOE: A hoe is a tool used to digging soil and to place cement mortar, concrete in head pan. 2. PICK AXE: It is a hand tool with hard metal head and wooden handle. This tool is used to excavate the soil. It is more suitable for hard soil which is quite difficult to dig with spade or hoe. 3. SPADE: A spade is tool contains metal plate at the end of long wooden handle. It is used to dig the soil for foundation trenches etc. 4. DIGGING BAR: A digging bar is a long straight solid metal rod with pin shape at the bottom used to dig the hard surfaces of ground. 5. MEASURING BOX: Measuring box is used to measure the quantity of cement, sand and aggregates used for making concrete mix. The volume of measuring box is generally 1 cum feet which makes it easy to measure concrete ratio. The general dimensions of measuring box are 300 x 300 x 400 mm. 6. HEAD PAN: Head pan is commonly used in construction sites made of iron or plastic. It is used to lift excavated