Civil Studs

Plane surveying is the survey in which the earth surface is assumed to be a plane and the curvature of the earth is ignored. The plane surveys extend only over small areas and the lines connecting any two points on the surface of the earth are treated as straight lines and the angles between such lines are taken as plane angles. Moreover In plane surveying, the area under consideration is taken to be a horizontal plane and the measurements plotted will represent the projection on the horizontal plane of actual field measurements. A horizontal plane is one which is normal to the direction of gravity as defined by “ Plumb Bob ” at a point, but due to the earth, the plane will be tangent to the surface of the earth at that point. For long enough area, there will be a difference between the area of horizontal plane & the area on the curved surface of the earth. It can be shown that for surveys up to 100 sq. miles in area, this difference

AGGREGATES

Aggregate are the inert materials, such as sand, stone, surkhi, used for mortar, cement concrete, Asphalt concrete, and other civil engineering applications. Aggregate , in building and construction , material used for mixing with cement , bitumen, lime, gypsum, or other adhesive to form concrete or mortar . The aggregate gives volume, stability, resistance to wear or erosion, and other desired physical properties to the finished product. Commonly used aggregates include sand , crushed or broken stone, gravel (pebbles), broken blast-furnace slag , boiler ashes (clinkers), burned shale, and burned clay . Depending upon size aggregate may be classified as: • Fine Aggregate • Coarse Aggregate Fine Aggregate Those particles passing the 9.5 mm (3/8 in.) sieve, almost entirely passing the 4.75 mm (No. 4) sieve, and predominantly retained on the 75 µm (No. 200) sieve are called fine aggregate. e.g Sand Chemically sand = silica (SiO2) Fine minerals The order

Field Compaction Methods

Compaction is the densification of soil materials by the use of mechanical energy. Soil is compacted by removing air and water from its pore space. There exists a certain amount of moisture that soil can have where a maximum unit weight is obtained. When the soil is compacted to this state it is referred to as the maximum moisture/ unit weight. The maximum Moisture/ unit weight is used exclusively to determine the degree of compaction of the earth back-fill. Objectives of Compaction:- · Increase the shear strength. · Increased bearing capacity for foundation support. · Reduce compressibility and smaller settlement of buildings and lesser deformation of earth structures. · Reduce permeability, leading to less seepage of water. · Improve stability and lower damage due to frost action. · Heavy/highway vs. building foundation compaction operations. · To reduce the degree of shrinkage and formatio

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