Some useful tips to enhance the longevity of concrete piles

If concrete is mixed perfectly and compacted to a solid impervious, the longevity of all the construction materials is significantly increased in a non aggressive atmosphere.

The strength of concrete is influenced by sulphate and sulfuric acid that takes place normally in soils, erosive chemicals existent in industrial waste in fill materials and organic acids and carbon dioxide existent in ground water.

A solid, properly compacted concrete can efficiently safeguard the concrete piles, pile cap and ground beams against the attack by sulphates. The low penetrability of dense concrete resists or significantly controls the ingress of the sulphates into the pore spaces of the concrete.

That's why high strength precast concrete piles are mostly recommended for application. Although these are not acceptable for all the site conditions and bored cast in situ / driven cast in situ piles, so, at the time of application, these should be designed perfectly to attain necessary degree of impenetrability and defiance to aggressive action.

Both high alumina cement and super sulphated cement are not suitable for piling work. As an alternative, reliance is provided on the resistance of solid impervious concrete that is formed with a low water cement ratio. Coating of tar or bitumen on the surface, metal sheeting or glass fibre wrapping filled with bitumen may be chosen.

A layer of heavy gauge polythene sheeting provided on a sand carpet or on blinding concrete is arranged to safeguard pile caps and ground beams on the underside. The vertical sides are safeguarded once the formwork is eliminated with the use of hot bitumen spray coats, bituminous paint, trowelled on mastic asphalt or adhesive plastic sheeting.

Preventative measures against the aggressive action caused by sea water on concrete should only be taken into consideration with regard to precast concrete piles. Cast in situ concrete is utilized only as a centering to steel tubes or cylindrical precast concrete shell pills. The precast concrete piles for marine condition, a minimum ordinary portland cement content of 360 kg/m3 and a maximum water cement ratio of 0.45 by weight should be chosen.



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Some outstanding ideas to design your home with Concrete

Besides, concrete, other materials like steel, fibre, plastic, glass, wood and other superior materials can also be used together with concrete to build up homes. Now-a-days, concrete is extensively utilized for the construction of commercial, residential, institutional, and industrial buildings due to it’s adaptability, cost-effectiveness and the easy accessibility of raw materials for production.

In recent times, concrete home construction is gaining popularity because of the factors like sustainability, green building, disaster resistance, energy conservation, and safety. To satisfy these requirements efficiently, the engineers offer some unique design ideas.

Concrete Home Design Ideas: Designers have provided different types of design ideas for the construction of concrete homes owing to its versatility and easy accessibility of construction materials. Motivations that put into effect or head over to new design ideas are dissimilar, as for example, some design ideas get inspiration from nature while some from energy efficiency, aesthetics, sustainability, and recycling materials.

Advantages of Concrete Homes:

1. Stable
One of the most outstanding properties of concrete is its strength which offers comfortable shelter from inclement weather, and minimizes property damage while safeguarding from severe weather and natural disasters.

2. Long-lasting
Future maintenance is not required for home as a result the construction cost is reduced significantly.

3. Adaptable
Concrete is a multifaceted material from which any shape and form can be developed. This features facilitates the designers to produce innovative designs on the basis of the demand of client and situations under considerations.

4. Eco-Friendly
The materials necessary to develop concrete are accessible in local areas. Recycled materials like recycled aggregate, pozzolanic cementitious materials like fly ash and silica fumes are utilized to build up concrete.

It results in decreasing CO2 emission throughout cement production since a smaller quantity of cement is required for production.

5. Advantages throughout life-cycle of the Structure
Concrete homes offer various advantages and benefits all through their life span. As for example, chills inside area of the house and consequently curtail energy consumption, and give protection against disasters like fire; hurricane; earthquake; and flood.

Besides, concrete contains low volatile organic compound and it does not impact indoor air quality. Finally, it can be recycled to develop recycled concrete aggregate.

To get some of the most outstanding and award-winning design ideas for construction of concrete homes, click on the following link theconstructor.org



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Why curing of concrete is important?

Curing offers the following functionalities :

1. Resist the concrete from getting dried throughout hydration. If this happens, the strength of the concrete is reduced significantly. The damage can’t be recovered. If concrete is dried, the cement grains will produce an impervious layer of hydration product around them, and it will resist recurring of hydration, though several occasion it is dampened again.

2. To maintain heat at the surface.

Curing is carried out for the following purposes :-

a. To get rid of frost damage (under 5°C, 40°F)
b. To raise initial strength
c. To minimize temperature gradients

When low temperatures decrease initial strength, the effect does not remain for a long time in case the concrete has not frozen, and it is consequently retained at higher temperatures. As a result, a sample that is retained at 5°C (40°F) will not completely hydrate (specifically if there exist a pozzolan in it), but even after a number of months it will hydrate again with higher temperature.

Since hydration occurs more slowly, cements containing pozzolans and GGBS normally need longer curing. It is therefore necessary that these concretes should be recognized on site, and cured sufficiently. The pozzolanic reaction will then produce extra hydration products to block some of the pores among the cement grains, and attain good strength.

Given below, some recognized process of curing :

• Cover materials (e.g., columns) in polythene once the shutters are detached.
• Spray with curing membrane as soon as detachment of shutters.
• Wrap slabs with polythene (and pour ground slabs on polythene).
• For heat retention, the polystyrene should be utilized on the back of shutters (particularly, steel ones)
• Just leave shutters in exact position for a few extra days (particularly wooden ones).
• 50 mm of sand is well suited on slabs.
• Ponding (i.e., developing a pool on the concrete surface) will be definitely most suitable.

Note about curing:

• Ensure that curing is provided immediately as possible. A few hours may provide significant effect.
• Spray-on curing membranes are less effective, and in windy conditions they should not be used. On complicated areas (like columns), they should be used as there is no other options.
• Keep in mind that PFA, GGBS and, especially, CSF requires much better curing (frequently 5 days, in spite of 3 days).
• Allowing the bleed water to dry off will lead to more bleeding, and plastic cracking.
• Slabs on ground should contain a polythene sheet that is arranged under them, to get rid of excessive water absorption with dry soils.



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Benefits of fresh concrete to be vibrated

Fresh concrete that should be vibrated provides huge benefits. Freshly placed, unconsolidated concrete normally contains full of entrapped air bubbles. Concrete can attain a greater compressive strength and density with least air content mechanically i. e. with the help of high frequency (fast, repetitive) vibrations.

Thus, the concrete fulfill the present needs with regards to strength and density. The vibrator produces high frequency vibrations which are delivered to the components of the fresh concrete.

• Frictional forces among individual particles are significantly minimized.
• A flow process is formed.
• Air bubbles, excess water and paste are congested via capillary action and surface tensions are discharged and evaded to the surface.

Benefits of concrete vibration

• Superior density and consistency
• Superior compressive strength
• Superior durability (e. g. de-icing salt)
• Perfect bond with rebar, specifically in thickly reinforced sections

• Greater bond among the individually “wet” on “wet” placed layers
• Better quality exposed (fair-faced) surfaces
• Utilization of drier mixtures results in necessitating less cement.

Recognize your effective compaction diameter: For practical uses and as rule of thumb, approximate value should be taken for the operating diameter i.e. 10 times the vibrator head housing diameter.

Proper spacing should be retained while compacting large surfaces.

Proper spacing should be maintained while vibrating fresh concrete in walls.

Internal vibrators with dia (Ø) 30 (1.2”), 38 (1 ½”) and 45 mm (1.8”) should not be utilized because of poor or non-existing overlapping of the effective compaction Ø. It will result in producing a defective or inexpensive vibration method.

For superior effective compaction Ø and for more suitable, inexpensive compaction (less insertions, less time) preferably the following should be utilized :-

• Vibrators with diameters 57 or 65 mm, on the condition that the rebar allows it.
• The concrete will be compacted flawlessly due to the overlapping.

It is found that consistently and horizontally extended layers offer the superior outcomes in concrete compaction with approximately 50 cm (20”) thickness.



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Plain cement concrete – Uses and formation method

The objective of plain cement concrete alias PCC is to arrange a firm impermeable bed to RCC in the foundation where the soil is soft and flexible. It is mostly applied over brick flat soling or devoid of brick flat soling.

It is also known as Cement Concrete (CC) or Blinding Concrete.

When, any reinforcement is not used inside the concrete, it is defined as the plain cement concrete. It’s just a blend of concrete ingredients.

Characteristics of Plain Cement Concrete - Given below, some vital characteristics of plain cement concrete:

• Compressive strength: 200 to 500 kilogram/square centimeter
• Tensile strength: 50 to 100 kilogram/square centimeter
• Density: 2200 to 2500 kilogram/cubic meter
• Stability: Outstanding

Applications of Plain Cement Concrete: PCC is mostly found in footings, grade slabs, and concrete roads. When the underlying soil is weak and flexible, brick flat soling is provided under PCC.

To form PCC, the following materials are utilized :-

Cement: Normally, the Portland cement is utilized as bonding material in PCC.

Fine Aggregate: Sand is employed as fine aggregate. The fineness modulus (FM) of sand should remain 1.2 to 1.5. FM stands for an index number that demonstrates the mean size of particles in sand. It is measured by carrying out sieve analysis.

Coarse Aggregate: Usually, the brick chips are utilized for developing PCC. It is also possible to utilize stone chips in these conditions. The size of the coarse aggregate remains 20mm downgrade.

Water: Pure drinkable water should be provided in PCC.

How to build up PPC?

With the following methods, plain cement concrete is formed.

The following tools are utilized for the production of PCC

• Wooden or Steel rammer
• Mixture machine (if any)

The Thickness of PCC: The thickness of PCC is normally 50mm over Brick Flat Soling (BFS). If you don’t use BFS below PCC then the thickness should be 75¬mm. When the PCC is used in car parking area then the thickness should be 75mmover BFS.

Ration of materials in PCC: The ratio of cement, sand and brick chips in foundation or basement should be 1:3:6. But, if it is applied in the car parking area, the ratio will be changed to 1:2:4.

The production method for PCC: If ready-mix concrete is applied, this step should be omitted. If PCC is produced through mixture machine then click “How to mix concrete by mixture machine”. If the concrete is mixed manually, get help by clicking on this link “how to mix concrete by hand”.

Placing and Compaction of PCC:

• Ensure that brick soling/sand bed level is perfect for PCC.
• Create formwork for PCC with wooden planks according to stipulated dimensions.
• There should be no dust and foreign materials in concreting area.
• The bed of PCC should be covered with polythene.
• Create level pillars of fresh concrete in the area at proper spacing but not in excess of 2m c/c both ways.
• Set the concrete softly from one side. Apply the mixed concrete within 45 minutes once the water is added.
• For compaction and finishing of PCC, wooden rammer should be used.
• The surface of PCC should be rough to combine future work prior to solidification of the concrete.

Curing of PCC: After PCC is placed for 24 hours, wet the concrete surface with water. Alternatively moist gunny bags can be used to cover the surface for minimum seven days.



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Types of formworks found in construction

Generally, steel or concrete is used in formwork to build part of the permanent structure. Temporary formwork can be struck and recycled from any inexpensive and easily worked material, timber, steel and GRC/GRP.

The formwork that should be utilized under the water, should abide by the following conditions :

a. Support the concrete in its designed profile during the plastic phase
b. Properly affixed into position.
c. Cover the concrete from scour, washout and abrasion till unless it gets solidified.
d. Endure mistakes in development level or alignment of adjoining work
e. Ability to resist the static and dynamic loading caused by concrete, tides, waves and currents.

It is designed in the context of the permanent works and be abandoned in situ or as temporary works either to be abandoned in situ or smitten and recycled.

The following types of formworks are mostly found :-

Ceiling Formwork: Ceiling formwork belongs to the type of formwork commonly found in structures/buildings.

The formwork sheeting comprises of sheeting boards or prefabricated sheeting panels. The formwork sheeting is located on squared timber formwork bearers to be provided on main bearers capturing the forces to round timber columns. With smaller rooms, the main bearer along with two columns develops a trestle. Diagonal board bracings are arranged to manage horizontally acting forces. The round timber columns are arranged on double wedges which function as stripping aid and correction device.

Beam Formwork: Beam formwork contains prefabricated formwork sheeting parts (sheeting bottom and side sheeting panels). Such individual parts are erected on the basis of the beam dimensions stated in the project. For prefabrication of the formwork sheeting parts, a special preparation table should be created on site.

Column Formwork: Same as beam formworks, the sheeting of column formworks is prefabricated based on the column dimensions from sheeting boards attached with cover straps.

The sheeting panels are arranged in a foot rim which is secured in the soil with steel bolts.

The foot rim consists of double-nailed boards. The foot rim must be exactly measured-in because it is decisive for the exact location of the column. It has the same functions as the thrust-board for foundation or beam formwork.

When the sheeting panels are implanted in the foot rim, vertical arch timbers are arranged to undertake the forces from the cover straps of the formwork sheeting.

Around the arch timbers, that contains the function of walers, column clamps of flat steel are braced with wedges or a rim of boards is provided same as the foot rim. Supplementary formwork tying with tie wires or steel screws is not required.

The distances of the clamps are mentioned in the formwork project. Generally, they are roughly 700 mm.

The column in the formwork is laterally fastened by diagonal board braces.



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Details about High Performance Concrete (HPC)

Now-a-days, High Performance Concrete (HPC) is gaining popularity. HPC denotes superior concrete performance throughout wet stage (mixing & placing process); with greater strength in hardened stage together with a greater strength in long-run as compared to normal concrete.

The HPC is comprised of different chemical cum mineral admixtures and fibres. In HPC, the proportions are designed, or engineered, to create the strength and durability required for the structural and environmental requirements of the project.

High-strength concrete contains a specified compressive strength of 8000 psi (55 MPa) or higher. Special mixing, placing, and curing practices are required to develop and manipulate high-performance concrete. Normally, comprehensive performance tests are essential to show compliance with specific project requirements.

High-performance concrete is mainly utilized in tunnels, bridges, and tall buildings due to its strength, stability, and high modulus of elasticity. It is also been applied in shotcrete repair, poles, parking garages, and agricultural applications.

High-performance concrete characteristics are developed for particular applications and environments; some of the properties that may be required include:

• High strength
• High early strength
• High modulus of elasticity
• High abrasion resistance
• High strength and permanence in rigorous environments
• Low permeability and diffusion
• Defiance against chemical attack
• High resistance against frost and deicer scaling damage
• Toughness and impact resistance
• Volume stability
• Ease of placement
• Compaction devoid of segregation
• Inhibition of bacterial and mold growth

High-performance concretes are developed with cautiously chosen high-quality materials and optimized mixture designs; these are batched, mixed, placed, compacted and cured with reference to the superior industry standards.

Normally, such concretes will contain a low water-cementing materials ratio of 0.20 to 0.45. Plasticizers are normally utilized to produce these concretes fluid and workable. High-performance concrete almost always contains a greater strength as compared to normal concrete.

High-early-strength concrete, also known as fast-track concrete, attains its specified strength at an initial age as compared to normal concrete. The time period in which a specified strength should be attained may vary from a few hours (or even minutes) to several days. High-early-strength is achieved by employing conventional concrete ingredients and concreting practices, although sometimes special materials or techniques are necessary.



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Difference Between Flexible Pavement and Rigid Pavement

The pavement designing is complicated task in Transportation Engineering. The most recognized methods for pavement design are Rigid pavement and Flexible pavement. The pavement surface has good longevity and it can resist the load operating from the wheel tyres.

Given below, the functional requirement of highway pavements :-

1. Flexible pavement and Rigid pavement contain superior riding quality
2. It should be less slippery
3. It should be rigid
4. It should contain adequate friction keeping the power of the vehicle unchanged.

Variation among Rigid Pavement and Flexible Pavement

1. Flexible Pavement

a. Load is transmitted from grain to grain to the lower layers
b. The design is totally based on the subgrade strength.
c. IRC 37-2012 code is applied for making the design of flexible pavement
d. The strength of flexible pavement is influenced by the aggregate interlock, particle friction and cohesion.
e. Flexible pavement demonstrates the deflection of subgrade at the surface of the pavement.
f. Design life lasts for 15 years.

Rigid Pavement:

1. Rigid pavement contains a strong flexural strength that is considered as the vital factor of design.
2. Rigid pavement contains a concrete layer at the top, the base course and soil subgrade remain underneath.
3. Rigid pavement disperses the load over a broad area due to its high flexural strength.
4. Load is transmitted through slab action.
5. The total thickness of the pavement remains under flexible pavement.
6. IRC: 58-2011 is utilized for making the designing of Rigid pavement.
7. Design life extends for 30 years



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Some useful tips on reinforced concrete design

While designing the reinforced concrete members, it is necessary to check the steel reinforcement in jobsite prior to arrange concrete. Besides, ensure the concrete foundations, beams, columns, etc. are constructed as per design norms. Often, it is observed that steel beam stirrups employed in reinforced concrete design, are not installed properly.

The beam stirrups are extensively utilized in residential construction. In order to produce perfect architectural design and satisfy building occupant requirements, the sizes of concrete beam are made thinner and their lengths are increased.

In our experience, this has been the result of architectural design and. The higher cost of foundation components like drilled piers is also a major concern. To lessen the requirement of extra piers, the lengths of concrete beam are raised and it leads to the application of steel stirrups.

Concrete beams differ in depth. The shear strength of the beam will be increased by making beam deeper. For insufficient depth, steel stirrups should be included to raise the shear strength of the beam. These stirrups generally belong to one piece of steel that is twisted into a rectangular shape. Often small diameter steel like #3 and #4 rebar is applied. The stirrup normally wraps around the bottom and top bars of the beams.

It is essential to indicate the size, distance and position along the length of the beam where the stirrups will be assigned. Besides, the dimensions of stirrup should also be indicated in the sections in order that the stirrup is manufactured before installation.

Stirrups are suitable for the areas of high shear, like bearing points and under large point loads.

The installer should take proper care for fabrication of the stirrup from one piece of steel and sufficiently overlap each end (speak to the Structural Engineer or refer to the ACI code for variations). Sometimes, the stirrup is not pre-fabricated and the installer attempts to produce the stirrup in the field, once the horizontal bars are already in position. It is normal since the stirrup is built up from two pieces with insufficient lap splice.

The method is simple to set up a stirrup simultaneously the horizontal reinforcement is being installed. To avoid last-minute modifications, it is recommended to consult with the Structural Engineer with any confusion regarding size, shape, spacing and installation of stirrups before inspection.



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How to repair concrete with Dry Pack Mortar Method

The purpose of dry pack mortar is to repair the concrete surfaces with cracks or holes of depth greater than or equal to the minimum dimension of the repair area. The holes usually discovered on concrete surfaces are cone bolt holes, she bolt holes, holes formed with ties etc.

Dry pack mortar should not be used for shallow cracks, fully extended holes i.e., from one side to other side, space behind reinforcement etc.

Dry pack method involves the following steps for executing repairing work to concrete.

1. Arrangement of Hole Inner Surface
2. Arrangement of Dry Pack Mortar
3. Using Dry Pack Mortar
4. Curing of Dry Pack Repair Area

1. Preparation of Hole Inner Surface

a. Prior to use dry pack mortar, the surface or hole to be repaired should be cleansed, washed and dried perfectly. Also they should not contain any damaged pieces of aggregates.
b. The inside surface of hole should have been rough to create superior bond. If the surface is smooth, it should be roughened with tapered reamer or star drill.
c. Usually, there exist three methods to develop the inside surface area of holes for maintaining superior bond with dry pack mortar.

Method – 1

a. Bonding grout is used to brush the inside surface of hole. Bonding grout is made of cement and fine sand in the proportion 1:1.
b. Now, the dry pack mortar is applied prior to bonding mortar becomes dry to make superior bond among mortar and surface.
c. When bonding grout is used, ensure that no free surface water exists in the hole so that the hole remains fully dry.

Method – 2

a. By applying wet rags or burlap, the hole is pre-soaked all night with and permitted to dry.
b. When the hole is partly dried or comprises of some amount of surface water, then spray dry cement on to the surface with small brush.
c. The cement will consume free water and develops a layer on the surface. Extra cement still in dry form is eliminated with jet of air so that dry pack can be applied on the surface.

Method – 3

a. Under this method, superior bond among dry pack mortar and surface is formed with epoxy bond resins
b. Epoxy resin is blended and used on the surface with brush.
c. Ensure that the concrete temperature should not exceed at the time of using epoxy or else it may burn or dry up the epoxy promptly.
d. As soon as epoxy is used, instantly use the dry pack mortar prior to epoxy gets dried out.
e. Epoxy bond resin can resist the hydration of water to adjacent concrete surface.

To get more details about dry pack mortar, go through the following link theconstructor.org

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Benefits of post-tensioning concrete slabs in building

Post-tensioned concrete slabs in buildings provide various benefits over reinforced concrete slabs & other structural systems toward both single and multi-level structures. Described below, some of the advantages of the slabs :-

Longer Spans: Longer spans are utilized to lessen the number of columns. It leads to bigger, column free floor areas which significantly enhance the adaptability of application for the structure as well as leads to greater rental returns.

Entire structural cost: The complete cost of materials, labor and formwork which are essential to build up a floor is decreased for spans higher than 7 meters and consequently leads to huge cost savings.

Minimized floor to floor height: Thinner slabs are utilized for the similar imposed loads. The decreased section depths facilitate least building height together with consequent savings in facade costs. As a substitute, toward bigger buildings, it facilitates more floors to be developed inside the original building envelope.

Deflection Free Slabs: Unwanted deflections under service loads are virtually removed.

Water-resistant slabs: Post-tensioned slabs are designed to remain free from cracks and as a result water-resistant slabs should be formed with proper design, detailing and construction. The selection of concrete mix and curing method together with standard workmanship are also very important.

Early formwork stripping: The earlier stripping of formwork and curtailed backpropping requirements facilitate rapid construction cycles as well as fast reprocessing of formwork.

Materials Handling: The decreased material quantities in concrete and reinforcement significantly offer benefit to on-site carnage requirements. The stability of post-tensioning strand is roughly 4 times that of traditional reinforcement. So, the whole weight of reinforcing material is considerably minimized.

Column and footing design: The decreased floor dead loads are applied to create cost-effective design of the reinforcement concrete columns and footings. In multi-storied buildings, decreased column sizes may raise the floor net rentable area.



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Some vital methods for concrete curing

METHODS OF CURING :- Based on the type of construction work, the curing of concrete is done with the use of the following processes :-

1) COVERING: Under this method, wet gunny bags or hessian are utilized to wrap the newly developed concrete surface. This process is very effective for horizontal and vertical surface.

2) PONDING: Under this process, the entire surface is segregated into rectangular or square cages with the development of tiny clay bunds and these cages are filled with water occasionally building small ponds. This process is ideal for curing horizontal surfaces like floor, pavements etc.

3) SUBMERGING IN WATER: Pre-cast concrete members are over and over again cured by submerging them under water.

4) STEAM CURING: With this process, steam under pressure is sprinkled over the concrete surface. This process is very useful for pre-cast members.

5) SPRINKLING: Under this process, the water is sprinkled repeatedly over the concrete surface to keep the surface wet.

6) CURING WITH CHEMICAL: Under this process, water is sprayed over the surface as soon as specific amount of hygroscopic salt like NaCI, CaCletc are added. It helps to engross moisture from the atmosphere.

(7) MEMBRANE CURING: Under this process, concrete surface is wrapped with water proof membrane like wax emulsion, bitumen emulsion etc. The membrane stops the vaporization of water from concrete surface.

Article Source: www.civilnoteppt.com

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Detail lists of useful construction tools

Given below, the detailed lists of various useful construction tools and their applications :-

Hoe – It is effective for digging and arranging concrete, cement mortar in head pan. Hoe is also useful for excavating the soil but here the metal plate is set with acute angle to the wooden handle.

Head Pan – It is utilized to transmit materials. Head pan is built with iron to uprise the excavated soil or cement or concrete to the construction site etc. it is mostly found in construction sites.

Masonry trowel – The objective of this tool is to organize cement mortar. It refers to a hand trowel that is applied in brickwork or stonework for the purpose of leveling, dispersion and shaping mortar or concrete.

Measurement Tape – It is employed to examine the thickness, length, widths of masonry walls, foundation beds, excavated trenches etc.

Plumb Bob - It is applicable for verifying the vertical alignment of the structures. It comprises of a solid metal bob attached with the end of a thread. It can also be applied in surveying to level the instrument position.

Wheel Barrow – It is useful for carrying out cement mortar or any materials. Often, it is utilized to estimate the quantities of materials for site level concrete mixing.

Concrete Mixer – It is a machine that is used for blending the concrete perfectly with water, fine aggregate, coarse aggregate and cement at construction site.

Vibrator - It is utilized to vibrate the concrete when pouring is started. For the purpose of workability, water is added to concrete. To get rid of that, vibrators are applied.

Bump Cutter/Screed – The objective of this tool is to level fresh concrete surface particularly in slab concrete.

Wooden Float/wooden rendering float - This tool is useful for providing a flat finish to the plastered area.

Crow Bar - This tool is found in formwork to eliminate nails from boards. Crow bar is also applied for digging the ground and taking out the roots of trees in the ground, nails etc.

Framing Square - This tool is mostly found in Brickwork, Plastering to verify exact angle.

Line Level - This tool is required to verify horizontal level in brickwork, plastering , flooring and tile works.

Flat Pry Bar - This tool is found in shuttering and often utilized to modify the column formwork to align.

Digging bar - This tool is used to divide and unloose the compacted / hard surface area. Digging bar refers to a solid metal rod having pin shape at the bottom. It is also utilized to dig the hard surfaces of ground.

For more information, go through the following link www.civilology.com



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How to perform slump cone test for testing the workability of concrete

This construction video tutorial is based on slump cone test. It is one of the most recognized field tests on fresh concrete.

Slump test is undertaken to evaluate the functionality of fresh concrete as well as verify the water ratio and the consistency of concrete from batch to batch.

The instruments which are used in slump test comprise of a mould shaped like the frustum of a cone having the following dimensions :-

Bottom Diameter : 200 mm
Top Diameter : 100 mm
Height : 300 mm
Tamping rod of steel should contain diameter of 16 mm, 600 mm long and rounded at one end.

The following methods are used to work out slump :-

nternally and externally cleanse the inner surface of mould without applying any grease or oil.

Fill the mould with concrete in 4 layers.

Tamp each later with 25 strokes of the rod to get rid of bubbles and voids.

Allocate the strokes consistently over the whole cross-section of the mould.

The rod should infiltrate each bottom-line layer.

By applying a trowel, eliminate surplus concrete after the top layer.

Take away mould gradually and vertically.

The concrete will slump or slide.

Calculate the slump height in mm.

To maintain normal functionality, the slump should not be over 50 mm.

Cleanse the slump cone.

To get more detailed information, go through the following video tutorial.

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