Friday, 13 October 2017

Various types of cement with IS codes

In this construction video tutorial, the renowned civil engineer Parag Pal provides brief demonstration on various types of cement containing IS codes and characteristics of cement grades as well as various usages of cement.


Categories of cement :-
OPC (ordinary Portland cement) – It’s IS code is 269-1976 and it is utilized for general construction.

Low heat cement – It’s IS code is 269-1976 and it is employed for hefty construction.



Rapid Hardening Cement – It’s IS code is 8041-1990 and it is applied for eliminating formwork rapidly.

Pozzolona Cement – It’s IS code is 1489 – 1991 and is it used as good resistance to chemical.

High Strength Cement – It’s IS code is 8112 – 1989 and it is used for pre-stressed concrete.

Hydrophobic cement – It’s IS code is 8043 – 1991 and it is used for water proof construction.

Grade of cement is based on the crushing strength of a cement mortar cube of size 70.71 mm containing surface area of 51 cm2. It is tested in 28 days.


For more information, watch the following video.

Tuesday, 10 October 2017

How to resist segregation in concrete

If the concrete mix is not uniform, the concrete components are detached and it is known as segregation in concrete. The flow test demonstrates the cohesion of the concrete mix. Due to inconsistency, the greater particles of concrete aggregate will detach and proceed towards the edge. Segregation may also occur when concrete mix is arranged on a sloppy surface. Usually, a cement particle intends to depart from the center of the concrete mix and abandoning the coarser material behind. It is difficult to quantify segregation but an expert can detect it easily.

The strength of a segregated concrete may change frequently and due to this cracking and leakages in concrete may occur. So, in order to retain the durability of your structure, the segregation of concrete should be avoided.

Given below, some helpful tips to get rid of or minimize segregation:
01.The concrete mix should have been correctly designed with finest quantity of water that is not too wet nor too dry.

02. Ensure the concrete is perfectly blended at the exact speed in a transit mixture for minimum two minutes. Examine the performance of mixer on daily basis relating to tolerable consistency of distribution of components in each batch.

03. Properly ship the concrete mix. Select the shortest route for shipping of concrete mix.
04. Arrange the concrete in its final position in quickest possible time. The concrete should not be arranged from large heights.

Image Source : onlinecivilforum.com
05. Formwork should be resistant against water in order that paste should leakage from the forms. Never vibrate formwork.
06. Do not let concrete to flow.
07. Utilize the vibrator properly and never utilize it to expand a heap of concrete over a bigger area.
08. Vibrate the concrete for just the exact time (not too long, not too less).
09. Apply chemical admixtures like air entraining agent in the mix. Entrained air minimizes the risk of segregation.

10. If any segregation is found in concrete, initiative should be taken for remixing to make it uniform again.


Article Source : https://gharpedia.com

Wednesday, 4 October 2017

Spreadsheet for rate analysis in RCC

This construction article provides brief explanation on how to make rate analysis for Reinforced Concrete (RCC) work.

To perform rate analysis, the initial step will be calculating the labour, materials, equipments and miscellaneous items toward specific quantity of reinforced concrete.


The next step should be finding out the element of structure for which the RCC rate analysis is applicable, because the quantity of reinforcement steel fluctuates with slabs, beams, columns, foundation, RCC Roads etc., while the quantity of other materials like sand, coarse aggregate and cement remain unchanged with the similar mix design (mix proportion) of concrete.

Image Source : theconstructor.org


Labour rates for reinforcement work modifies with type of structural element because the quantity of reinforcement steel modifies. The Quantity of materials like sand, cement and coarse aggregates fluctuate with mix design like M15 (1:2:4), M20 (1:1.5:3), M25, M30 etc..


Necessary data for RCC Rate Analysis:

1. Computation of materials
a) Bags of cement necessary
b) Volume of Sand necessary
c) Volume of Coarse Aggregate necessary
d) Computation of Reinforced Steel

2. Labour Requirement for 1m3 of RCC

3. Equipments and sundries

4. Contractor’s Profit

To gather more detailed information, go through the following link.
https://theconstructor.org/practical-guide/rate-analysis-for-reinforced-concrete/6954/

Monday, 25 September 2017

Various types of scales in surveying

This construction article sheds light on various types of scales employed in Surveying…

The scales are categorized as follows:

1. Plain Scale
2. Diagonal Scale
3. Vernier Scale
4. Scale of chords



Plain Scale

On Plain Scale, it is reasonable to calculate two dimensions only. As for instance, measurements like units and lengths, metres and decimetres etc.

The engineers, Architects and Surveyors generally employ six different plain scales in metric.



Image Source : http://www.civilprojectsonline.com/


Diagonal Scale

On diagonal scale, it is reasonable to calculate three dimensions like metres, decimetres and centimetres, units , tens and hundreds; yards, feet and inches etc.
A short length is seperated into number of parts by applying the principle of equivalent triangle in which sides are proportional.

1-1 represent 1/10 PQ
2-2 represent 2/10 PQ
9-9 represent 9/10 PQ



Vernier Scale

It is an effective tool for measuring the fractional part of one of the smallest divisions of a graduated scale.

It generally contains a small auxiliary scale that slides side by side of the main scale.

Least count of the vernier = the variation among smallest division on the main division and smallest division on the vernier scale.

Scale of Chords

With scale of chords, it is possible to estimate an angle and is marked on either on rectangular protractor or an ordinary box wood scale.

Article Source : http://www.civilprojectsonline.com

Wednesday, 20 September 2017

Different types of surveying process

In this construction video tutorial, Ms.C.S.Suganya, the renowned assistance professor in civil engineering department, has briefly explains surveying and it’s different categories.

The surveying is primarily segregated in two parts :-

Geodetic Surveying

Geodetic surveying refers to the survey under which the curvature of the earth is considered and superior degree of perfection in linear and angular observations is gained. The geodetic surveys spread over big areas and lines relating any two points on the surface of the earth are taken as arcs. To workout their predictable distances on the plans or maps, the rectification for the earth’s curvature is employed to the calculated distances. The angles among the curved lines are considered as spherical angles. A knowledge of spherical trigonometry is required for creating measurements for the geodetic surveys. The area remains at 250 kilometer square.


Plane Surveying

Plane surveys are mostly recognized process of surveying and here, the earth is taken as a flat or "plane" surface. It is useful for small-scale surveys in restricted areas, the curvature of the earth does not provide any impact on the results, consequently, the calculations and results can be referenced to a plane or flat surface. The surveying is done for less than 250 kilometer square.


Secondarily, the surveying is segregated into the following parts :-



Land Surveying
A land survey, or simply survey, stands for the scientific process of calculating the dimensions of a specific area of the earth's surface, along with its horizontal distances, directions, angles, and elevations.


Hydrographical Surveying
Hydrographical survey belongs to the science of measurement and explanation of features which impact maritime navigation, marine construction, dredging, offshore oil exploration/offshore oil drilling and relevant activities.
Astronomical Surveying

An astronomical survey refers to a general map or image of a area of the sky which requires a definite observational target. On the other hand, an astronomical survey may contain a set of various images or spectra of objects which contribute to a common type or feature.

To get more detailed information, watch the following video tutorial.

Saturday, 16 September 2017

Some useful tips on concrete curing

Curing concrete is a complicated method that entails preservation of exact temperature, humidity, circulation, and other aspects. If Cracks occur, the strength of cement is impacted because of insufficient arrangements for these controls. Crystals form with reaction of water with Portland cement.

Curing makes sure that the concrete gains its optimal strength. The strength of concrete is influenced by crystal growth inside the concrete matrix. These crystals develop because of the hydration i.e. the reaction among the water and Portland cement. If water is insufficient, the crystals fail to develop and for this reason the concrete can’t gain the optimal strength. The existence of water allows the crystal development that enfolds the gravel and sand mix, inducing interweaving with each other.



Controls During Curing

Keeping exact curing temperature is vital so that the hydration reaction remains unaffected. If the concrete is very hot, the hydration reaction will be so fast for a proper crystal growth. Therefore, concrete fails to gain accurate strength. If the reaction becomes exothermic, variance in temperature will be produced inside the concrete and it may lead to cracks. Rough surface and a porous concrete structure may be formed because of Inappropriate hydration on the concrete surface. Such porous concrete structures will allow calcium hydroxide to contact the concrete surface that leads to efflorescence. Besides, the concrete structure becomes feeble. Other significant points to be considered throughout the curing are perfect humidity, circulation, insulation, and time control.



Image Source : precast.org


Autogenous Shrinkage

Autogenous shrinkage takes place if the shape of the cement paste is lost because of insufficient water for hydration. Autogenous shrinkage occurs when the volume of the hydrated cement products is under the volume of the cement and water mix prior to starting of hydration. It does not occur for external factors like loss of moisture or temperature variations. Autogenous shrinkage is generally not important in concrete with a water-cement ratio of more than about 0.4. Though, as this ratio is reduced under that limit, autogenous shrinkage is expected to be raised. There will not be sufficient water in the concrete for curing if amalgamated with a water cement ratio below 0.40. In the initial phase, when the tensile strength is low, and concrete is below the effects of high temperature divergence, concrete may crack due to occurrence of autogenous shrinkage.



Improved Curing

The particular controls of temperature, humidity, and time which are vital throughout the process of curing can’t be achieved precisely and for this reason perfect concrete strength and other characteristics are impacted. Self-curing technologies becomes popular as it applies substances for internal curing. Proper materials are used to the wet concrete surface to reduce the loss of water from the concrete. The materials produced are emulsions of paraffins which are dispersed on to the surface. A superior concrete is generated with minor permeability that has superior strength and longevity.

Article Source : http://www.brighthubengineering.com

Wednesday, 13 September 2017

Glass Fiber Reinforced Concrete (GFRC) – Definition and various advantages

Glass fiber reinforced concrete belongs to an engineered material that comprises of cement, polymers, and glass fibers. These materials are implanted in the cementious matrix. The GFRC properties are impacted by the glass contents, mix design, and production process. GFRC is mostly suitable for outside applications.



Glass fiber reinforced concrete is mainly a concrete material that employs glass fibers for the reinforcement, as an alternative to steel. Generally, the glass fibers have resistance capacity against alkali. Alkali resistant glass fiber is very useful because it provides a greater resistant to the ecological effects. GFRC is formed by amalgamating cement, glass fibers, and polymers. It is usually casted in thin sections. As the fibers are free from rust like steel, safeguarding concrete coat is not essential for controlling rust. The weight of thin and hollow products formed with GFRC is significantly lighter as compared to the usual pre-cast concrete. The material characteristics are impacted with the concrete reinforcement spacing, and the concrete reinforcement mesh.



Image Source : www.tuf-bar.com




Benefits of using GFRC
  • GFRC is made of minerals and it can’t be burnt easily. If it is uncovered to a flame, the concrete acts as a thermal regulator. It safeguards the materials set with it from the flame heat.
  • These materials are reasonably lighter as compared to the traditional materials. Therefore, the process is quick and easy for installing them. Concrete may be formed in thin sections.
  • Casting for GFRC can be done into any shape of columns, wall panels, domes, moldings, and fireplace surrounds.
  • High strength is gained with GFRC as it is strong and resistant to cracking. It contains a high ratio of strength-to-weight. Therefore, the GFRC products are long-lasting and light. Due to light weight, the transportation costs are considerably less.
  • GFRC is examined in the laboratory and also in the actual installations, and predicted to endure as long as pre-cast concrete. In several ecological conditions, like when uncovered to salts or moisture, GFRC is expected to function in a superior manner because of the non existence of steel reinforcement that may decay.
  • GFRC is thin and tough, with weight being 75% to 90% less in contrast to solid concrete. Less weight reduces the load functional on the structure. The light weight and tough material facilitates suppleness in design, and minimizes the effect on environment.
  • Superior strength improves the capability to undergo seismic loads.
  • GFRC is less susceptible to weather effects and more defiant to freeze thaw than the normal concrete.
  • Evaluation of GFRC to Precast Concrete.



The elasticity and compactness of the GFRC is better as compared to precast concrete. The proportion of cement to sand for GFRC is roughly 1:1, whereas for precast concrete it is 1:6. The glass fibers contained to reinforce the concrete creates significantly superior impact strength and reduces permeability to water and air as compared precast concrete. GFRC appears as a natural stone and allows the designer to have greater flexibility in form, color, and texture.

Various types of cement with IS codes

In this construction video tutorial, the renowned civil engineer Parag Pal provides brief demonstration on various types of cement contain...