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POINTS TO BE OBSERVED WHILE SUPERVISING THE BRICK MASONRY WORK

Following points are to be carefully attended while supervising the brick masonry work.

The bricks to be used should confirm the requirements of the specification of the work.The brick should be saturated with water so as to prevent absorption of moisture from the mortar. This is effectively done by providing a tank at the site of work and by immersing the bricks for a period of atleast 2 hours before the bricks are actually placed in a position.The bricks should be properly laid on their beds. The mortar should completely cover the bed as well as the sides of bricks. The bricks should be laid with the frog uppermost.The brickwork should be carried out in proper bond.The brickwork should comply with the requirements of the specifications for the work.The mortar to be used for the work should be of quality and of proportion as specified.As far as possible, the brickwork should be raised uniformly. But when this is not possible or when a cross wall is intended to be inserted after somet…

WHICH TYPE OF LOAD ARE AFFECTIVE TO FOUNDATIONS

There are three types of loads on the foundations: 
1. Dead load 2. Live load 3. Wind load
1. Dead load :  This is the load of the material used for the various components of a building such as walls, floors, roofs etc. All permanent loads are thus included in the dead load. Sometimes, the provision for the future construction of a partition wall is made by allowing a dead load of 10 kg/sqm of the floor area. It should be seen that the dead load of partitions constructed in future under this provision does not exceed the allowance made. 
2. Live load :  This is the movable load on the floor and hence it is variable. It is also sometimes known as superimposed load. It includes the load of persons standing on the floor, weight of snow on a roof etc. For the purpose of Design. The Live load is converted into equivalent dead load. Following table 1 gives the values of equivalent dead loads for floors of different types of buildings. Further, a percentage reduction is applied in the Design of pie…

DEVELOPMENT LENGTH OF BARS FOR DIFFERENT STEEL AND DIFFERENT GRADE OF CONCRETE

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WHICH METHODS ARE USED TO DETERMINE THE BEARING CAPACITY OF SOIL

Methods for determining the bearing capacity of soil

The bearing power of soil can be determined by any one of the following two methods:
1. Method of loading
2. Method of dropping a weight

1. Method of loading:
The material required for this test are given below.
1. A square steel plate
2. Wooden table
3. Wooden pegs
4. Dumpy level
5. Rolled steel section
6. Sand bags

The procedure to carry out the test is as follows:
1. A square pit of required size is excavated upto required depth. The side of the pit should be at least five times the side of steel plate. At the centre of the pit,a square hole is dug of size equal to steel plate. The bottom of the hole should correspond to the foundation level and the ratio of depth to breadth of pit should be made equal to the ratio of depth to break of hole.
2. The bottom of the hole is made level by scraping only and it is well protected against disturbing forces before and during the test.
3. The steel plate is put up in the hole and then the pl…

METHODS TO MEASURE MOISTURE CONTENT OF AGGREGATES

Determination of moisture content in aggregate is of vital importance in the control of the quality of concrete particularly with respect to workability and strength. The measurement of the moisture content of aggregates is basically a very simple operation. But it is complicated by several factors. The aggregate will absorb a certain quantity of water depending on its porosity. The water content can be expressed in terms of the weight of the aggregate when absolutely dry, surface dry or when wet. Water content means the free water, or that held on the surface of the aggregate or the total water content which includes the absorbed water plus the free water, or the water held in the interior portion of aggregate particles. The measurement of the moisture content of aggregate in the field must be quick, reasonably accurate and must require only simple appartus which can be easily handled and used in the field. Some of the methods that are being used for determination of moisture content…

HOW THE MOISTURE CONTENT AND WATER ABSORPTION OF AGGREGATE AFFECT THE CONCRETE.

Some of the aggregates are porous and absorptive. Porosity and water absorption of aggregate will affect the water/cement ratio and hence the workability of concrete. The porosity of aggregate will also affect the durability of concrete when the concrete is subjected to freezing and thawing and also when the concrete is subjected to chemically aggressive liquids. The water absorption of aggregate is determined by measuring the increase in weight of an oven dry sample when immersed in water for 24 hours. The ratio of the increase in weight to the weight of the dry sample expressed as percentage is known as absorption of aggregate. But when we deal with aggregates in concrete the 24 hours absorption may not be of much significance, on the other hand, the percentage of water absorption during the time interval equal of final set of cement may be of more significance. The aggregate absorbs water in concrete and thus affects the workability and final volume of concrete. The rate and amount…

WHAT IS AAC BLOCK?

INTRODUCTION
Autoclaved aerated concrete (AAC) block is also known as Autoclaved cellular concrete (ACC) block. It is a lightweight, precast, foam concrete building material which is suitable for producing concrete masonry unit (CMU) like blocks. The material composed of quartz sand, calcined gypsum, lime, cement, water and aluminum powder. AAC products are cured under heat and pressure in an autoclave. AAC blocks are Invented in the mid-1920s, by the Swedish architect and inventor Dr. Johan Axel Eriksson.  AAC simultaneously provides structure, insulation, and fire- and mold-resistance. Forms include blocks, wall panels, floor and roof panels, cladding (fa├žade) panels and lintels.

AAC is a highly thermally insulating concrete-based material used for both internal and external construction. Besides AAC's insulating capability, one of its advantages in construction is its quick and easy installation, because the material can be routed, sanded, or cut to size on site using standard ca…

WHAT IS WAFFLE SLAB? CONSTRUCTION PROCEDURE AND ADVANTAGES, DISADVANTAGES OF IT.

WAFFLE SLAB
A waffle slab is a concrete slab made of reinforced cement concrete with concrete ribs which are running in two directions. It can be shown from below side and slab has a plain top. Due to the underneath ribs, It is also called ribbed slab. Waffle slab are preferred for longer span which are greater than 12 m. They are much stronger than flat slabs, flat slabs with drop panels, two-way slabs, one-way slabs, and one-way joist slabs.A waffle slab is flat on the top. The top portion of the slab having a thickness of 100 to 120 mm. Below portion of the slab is made of ribs which are intersected to each other. The thickness of these ribs are generally 100 to 200 mm and overall depth of slab is 300 mm to 600 mm Dependent on the span of slab. These ribs create small square blocks. These square blocks has sized of 600 to 1200 mm depending on design. Sometimes the ribs creates triangular blocks. The ribs of waffle slab are formed by the ready made mould, on which the concrete would …

WHAT IS RAINWATER HARVESTING?

Water is an important natural resource and the need of water is very necessary for organisms to live. It is very important for human survival and existence. We use water for drinking,
irrigation, industry, transport and for the production of hydro-electricity. Water is a cyclic resource which
can be used again and again after cleaning. The best way to conserve water is its rational use and more accumulation of water from rainfall.

Rain water harvesting:

Rain water harvesting is one of the most effective methods of water management and water conservation. It is the term used to indicate the collection and storage of rain water used for human, animals and plant needs. It involves collection and storage of rain water at surface or in sub-surface aquifer, before it is lost as surface run off.

Needs of rain water harvesting :

1. To overcome the inadequacy of surface water to meet the demands of people. 
2. To stop the declination in ground water levels. 
3. To enhance availability of ground water …

DEFINITIONS OF TERMS USED IN BUILDING

1. Amenities :
Amenities means roads, streets, open spaces, parks, recreational grounds, play grounds, gardens, water supply, electric supply,street lighting, drainage, sewerage, public works and other utilities, communication network, surface and convenience.

2. Amusement park :
A large outdoor area with fairground rides, refreshments, games of chance or skill and other entertainments.

3. Atrium :
It is also called plural atria. It means an unobstructed, multi storied open space within a building that covered from top with light weight or glazed roof.

4. Banquet hall :
It means a room or an enclosed space or building for the purpose of hosting any social events or ceremonies like marriage, reception, party etc. With accompanying food and beverages.

5. Basement :
I means the lower storey of a building having at least half of the clear floor height of the basement or cellar below average ground level.

6. Botanical garden :
It is a garden or an open space of land often with green houses for the cu…

WHICH LABORATORY TESTS ARE CONDUCTED TO CHECK QUALITY OF CEMENT

The following important tests are carried out for normal setting of portland cement :

1. Fineness test :
This test is conducted to check the proper grinding of cement. The fineness of cement is rested either by sieve method or air permeability method.
The percentage of residue left after sieving good portland cement in 90 micron IS(Indian standard) sieve should not exceed 10%.
A good portland cement should not have specific surface less than 2.25 sq.cm/kg, if found by air permeability method.

2. Consistency test :
This test is conducted to determine the percentage of water required for preparing cement paste of standard consistency. The consistency test is performed with the help of vicat's plunger apparatus which determines the initial and final setting time and normal consistency of portland cement.
The initial setting time of ordinary and rapid hardening cement should not be less than 30 minutes.
The final setting time of ordinary and rapid hardening cement should not be more than 600 …

WHAT IS PLASTERING WORK? PURPOSE OF IT AND CLASSIFICATION OF PLASTER WORK.

PLASTERING WORK
Plastering work is a process of covering the rough surfaces or unfinished surfaces like walls, ceilings, column and other building components with thin coat of cement mortar or other material to form a smooth and finished surface and gives an aesthetic appearance. It increases the durability of surface.
Purpose of plastering : 1.It provides flat, smooth and even surface. 2. It makes masonry or AAC block wall more durable. 3. It protects inner surface from atmospheric conditions. 4. It can resist the cracks which may develop in wall. 5. It provides suitable surface for painting or any other aspect. 6. It prevents the penetration of water. 7. It provides hard surface which do not scratched by the sharp things.
Classification of plaster
It may be classified based on three parameters which are given below. 1. Based on material 2. Based on Finishes 3. Based on coat
1. Based on material : Lime plaster : It involves the sand and lime as a main material. Generally it is non-hydraulic hydrated…

CIVIL SITE ENGINEER MUST KNOW THESE THINGS.

TOP THINGS THAT MUST KNOW BY CIVIL SITE ENGINEERS :

1. Minimum bars for square column is 4 nos and 6 nos for circular column.

2. Free fall of concrete is allowed maximum to 1.5 m height.

3. Appropriate water to cement ratio should be around 0.4 to 0.5.

4. Electrical conduits shall not run in column.

5. First class bricks should not absorb water more than 15% of its dry weight.

6.Minimum compressive strength of bricks is 3.5 N/mm2.

7. In steel reinforcement binding wire required is 8 kg per MT.

8. PH value of water for construction purposes should not be less than 6.

9. Initial and final setting time of cement is respectively 30 minutes and 600 minutes.

10. Curing days for ordinary portlnd cement should be minimum 10 days.

11. To find wieght of steel per meter, d2/162 formula has been used.

12.Minimum thickness of slab is 125 mm.

13. Minimum 3 specimens of cubes needed to determine average compressive strength of concrete.

14. Lapping is not allowed for the bars having diameters more than 36 mm.

15. …

TYPES OF FIBERBOARD USED IN BUILDING CONSTRUCTION.

Fiberboard is a type of engineering wood which is manufactured by binding or fixing the particles, wood fibers or boards of wood together with adhesives by applying the method of pressing or heating. 
Types of fiberboard in order of increasing the density include particle board or low density fiberboard (LDF), medium density fiberboard (MDF) and hardboard or high density fiberboard (HDF).


What is low density fiberboard or particle board?
It is a chip board which is manufactured from wood chips, sawmill shavings and other type of sawdust scrap with the help of resins or other suitable binder. The density of LDF is around 500 kg/m³.

Advantages :
1. It is a lightest and cheapest among fiberboards.
2. It has thermo-acoustic insulation properties, so they are very useful in speakers and in false ceiling of auditoriums, theaters etc.
3. It is eco-friendly material as it is uses wood waste such as sawdust, wooden shavings and wood chips.
It does not get distort easily.

Disadvantages :
1.Particle board…

LIST OF ADMIXTURES AND CHEMICALS USED IN CONSTRUCTION.

ADMIXTURES


PlasticizersSuperplasticizersRetarders and retarding plasticizersAccelerators and accelerating plasticizersAir-entraining admixturesDamp-proofing and waterproofing admixturesGas forming admixturesAir-detraining admixturesAlkali-aggregate expansion inhibiting admixturesWorkability admixturesGrouting admixturesCorrosion inhibiting admixturesBonding admixturesFungicidal, Germicidal, Insecticidal admixturesColouring admixtures
CHEMICALS
Concrete curing compoundsPolymer bonding agentMould releasing agentsPolymer modified mortar for repair and maintenanceProtective and decorative coatingsInstallation aidsFloor hardner and dust proofersNon-shrink high strength groutSurface retardersBond-aid for plasteringReady to use plasterGuiniting chemicalSome water proofing chemicals  Integral water-proofing compoundsMembrane forming coatingsPolymer modified mineral slurry coatingsProtective and decorative coatingsChemical DPCSilicon based water-repellent materialWaterproofing adhesive for tiles, …

WHAT IS SOUNDNESS OF AGGREGATE.

SOUNDNESS OF AGGREGATE

Soundness refers to the ability of aggregate to resist excessive changes in volume as a result of changes in physical conditions. These physical conditions that affect the soundness of aggregate are the freezing the thawing, variation in temperature, alternate wetting and drying under normal conditions and wetting and drying in salt water. Aggregates which are porous, weak and containing any undesirable extraneous matters undergo more than the specified amount of volume change is said to be unsound aggregates. If concrete is liable to be exposed to the action of frost, the coarse and fine aggregate which are going To be used should be subjected to soundness test.
The soundness test consists of alternative immersion of carefully graded and weighed test sample in a solution of sodium or magnesium sulphate and oven drying it under specified conditions.The accumulation and growth of salt crystals in the pores of the particles is thought to produce disruptive internal …

WHAT IS CONSTRUCTION BRICK? CLASSIFICATION OF BRICKS AS PER CLASS.

INTRODUCTION

A brick is rectangular in shape and of size that can be conveniently handled with one hand. Brick may be made of burnt clay or mixture of sand and lime or of Portland cement concrete. Clay bricks are commonly used since these are economical and easily available. The length, width and height of a brick are interrelated as below:
Length of brick = 2 × width of brick + thickness of mortar Height of brick = width of brick
Size of a standard brick (also known as modular brick) should be 19 × 9 × 9 cm and 19 × 9 × 4 cm. When placed in masonry the 19 × 9 × 9 cm brick with mortar becomes 20 × 10 × 10 cm.
However, the bricks available in most part of the country still are 9" × 4.5"× 3" and are known as field bricks. Weight of such a brick is 3.0 kg. An indent on top of brick called frog, 1–2 cm deep. The size of frog should be 10 × 4 × 1 cm. The purpose of providing frog is to form a key for holding the mortar and therefore, the bricks are laid with frogs on top.

Classif…