CIVIL ZONE

  There are different methods for testing of sand quality at construction site for concrete construction. Quality of sand is as much of importance as other materials for concrete. Aggregate most of which pass through 4.75 mm IS sieve is known as fine aggregate. Fine aggregate shall consists of natural sand, crushed stone sand, crushed gravel sand stone dust or arable dust, fly ash and broken brick (burnt clay). It shall be hard, durable, chemically inert, clean and free from adherent coatings, organic matter etc. and shall not contain any appreciable amount of clay balls or pellets and harmful impurities e.g. iron pyrites, alkalis, salts, coal, mica, shale or similar laminated materials in such form or in such quantities as to cause corrosion of metal or affect adversely the strength, the durability or the appearance of mortar, plaster or concrete.  The sum of the percentages of all deleterious material shall not exceed 5% . Fine aggregate must be checked for organic imp...

Concrete slump test  or slump cone test is to determine the workability or consistency of concrete mix prepared at the laboratory or the construction site during the progress of the work. Concrete slump test is carried out from batch to batch to check the uniform quality of concrete during construction .The slump test is the most simple workability test for concrete, involves low cost and provides immediate results. Due to this fact, it has been widely used for workability tests since 1922. The slump is carried out as per procedures mentioned in  ASTM C143 in the United States, IS: 1199 – 1959 in India and EN 12350-2 in Europe . Generally  concrete slump value  is used to find the workability, which indicates water-cement ratio, but there are various factors including properties of materials, mixing methods, dosage, admixtures etc. also affect the concrete slump value. Factors which influence the concrete slump test: Material properties like che...

Slow Sand Filtration Summary   First used in the U.S. in 1872, slow sand filters are the oldest type of municipal water filtration. Today, they remain a promising filtration method for small systems with low turbidity or algae containing source waters. Slow sand filtration does not require pretreatment or extensive operator control—which can be important for a small system operator with several responsibilities. What is slow sand filtration? Slow sand filtration is a simple and reliable process. They are relatively inexpensive to build, but do require highly skilled operators. The process percolates untreated water slowly through a bed of porous sand, with the influent water introduced over the surface of the filter, and then drained from the bottom. Properly constructed, the filter consists of a tank, a bed of fine sand, a layer of gravel to support the sand, a system of underdrains to collect the filtered water, and a flow regulator to control the filtration rate. No chemicals ar...

Introduction-  Most accidents can be prevented by taking simple measures or adopting proper working procedures. This handbook is intended to outline important issues on safety and health that should be paid attention to on construction sites for easy reference by the workers. If we work carefully and take appropriate safety measures, there will definitely be fewer work injury cases, and our sites will become a safe and secure place to work in .The Occupational Safety and Health Ordinance, which came into operation on 23 May 1997, covers most workplaces in order to protect the safety and health of employees at work. Other legislation applicable to construction sites includes the Factories and Industrial Undertakings Ordinance and its subsidiary legislation, particularly the Construction Sites (Safety) Regulations. Employees' Responsibilities Employees should cooperate with their employers and other persons in complying with the safety legislation and guidelines, and shou...