Making of Test Cubes From Fresh Concrete IS-456 has laid down the acceptance criteria of quality concrete. In all the cases, the 28-days compressive strength shall alone be the criterion for acceptance or rejection of the concrete. 7 days compressive strength of concrete can be carried out in order to get a relatively quicker idea … Read more
Unit Weight/Dead Weight of Construction Materials The tables given below give the unit weight or dead weight of some common construction material that is used by designer while computing load related calculation. 1. Bituminous Substance Item Weight (kg/m3) Anthracite coal 1550 Peat (dry) 560 to 640 Charcoal (light) 300 Coke 1000 Graphite 500 Crude oil … Read more
DESCRIPTION OF ROCK MASS CHARACTERISTICS Standardized geologic mapping and logging procedures should be used for describing rock mass characteristics. The types of information collected will depend on site access, extent of rock outcrops, and the criticality of the proposed structure to be constructed on or in the rock mass. A method proposed by the International … Read more
Measurement of Soil Compaction in the Field It is necessary in many instances to know the wet/dry densities of the soil in the field, especially before planning activities such as compaction. The same becomes particularly important in instances such as the construction of earth dams, embankments etc. to control the field compaction, that is, to … Read more
Standard Penetration Test (SPT) Procedure Aim To perform standard penetration to obtain the penetration resistance (N-value) along the depth at a given site. Equipment & Apparatus Tripod (to give a clear height of about 4 m; one of the legs of the tripod should have ladder to facilitate a person to reach tripod head.) Tripod … Read more
In order to determine the suitability of a particular soil it is essential to know the proportion of each material in the soil and also whether the particular material possesses the properties required of it. For instance, a road soil that is 95 percent sand will not cohere, and clay that does not possess the … Read more
Aggregates influence the properties of concrete/mortar such as water requirement, cohesiveness and workability of the concrete in plastic stage, while they influence strength, density, durability, permeability, surface finish and colour in hardened stage. Field Tests for Aggregate 1. Surface Moisture Content & Absorption The surface moisture in the aggregate, influences the water cement ratio, strength … Read more
On-Site Identification & Classification of Soil The principle terms used by civil engineers to describe soils are Gravel (particle size larger than 4.75 mm) Sand (particle size within 4.75 mm to 0.075mm) Silt & Clay (particle size less than 0.075mm) Most natural soils consist of a mixture of two or more of these constituents and … Read more
Slump Cone Test of Fresh Concrete Object This test is performed to measure consistency or workability of fresh concrete, where the nominal maximum size of aggregate does not exceed 38 mm using slump test apparatus. Reference Standards IS : 1199 – 1959 – Method of sampling and analysis of concrete. Equipment & Apparatus Slump cone (Height … Read more
Measurement of Density of Soil in place by Nuclear Density Gauge Purpose This is a quick method of determining the in-situ density of soil which is based on the radiation. Equipment For this test special equipment which measures in place density using gamma radiation is used. Gauge usually contains a small gamma source (about 10 … Read more