project report on mix concrete
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Showing posts with label College Notes. Show all posts
Showing posts with label College Notes. Show all posts
Tuesday, 26 June 2012
Partial cement Replaceable Material
An experimental program is conducted to develop new kinds of pozzolana from
other agricultural wastes apart from rice husk and rice straw. The study investigated the use of coconut husk, corn cob and peanut shell ash as cement replacement materials. A series of tests were performed to determine the chemical composition of coconut husk ash, corn -cob ash and peanut shell ash which are referred to as CHA, CCA and PSA respectively.
The mechanical properties of paste and mortar containing different percentages of ash replacement were investigated. Experimental results revealed that coconut husk ash and corn cob ash cannot be utilized as pozzolona while peanut shell ash can be classified as Class ‘C’ pozzolona according to ASTM Standards. Corn cob ash mortars possessed higher compressive strength. Among the four types of mortars tested for chemical attack, PSA mortars showed higher resistance against acidic attack.
Download :
http://www.ziddu.com/download/19766468/Partialcementreplaceablematerials2.pdf.html
other agricultural wastes apart from rice husk and rice straw. The study investigated the use of coconut husk, corn cob and peanut shell ash as cement replacement materials. A series of tests were performed to determine the chemical composition of coconut husk ash, corn -cob ash and peanut shell ash which are referred to as CHA, CCA and PSA respectively.
The mechanical properties of paste and mortar containing different percentages of ash replacement were investigated. Experimental results revealed that coconut husk ash and corn cob ash cannot be utilized as pozzolona while peanut shell ash can be classified as Class ‘C’ pozzolona according to ASTM Standards. Corn cob ash mortars possessed higher compressive strength. Among the four types of mortars tested for chemical attack, PSA mortars showed higher resistance against acidic attack.
Download :
http://www.ziddu.com/download/19766468/Partialcementreplaceablematerials2.pdf.html
High Performance Concrete
The current trend of use of superlatives in concrete technology may strike as
somewhat disconcerting to many .We had high strength concrete, hyperplasticiser, and
superplasticisers, very reactive Pozzolana, and now high performance concrete. It is difficult to imagine any concrete being manufactured and used, which is not intended to perform to the extent; high performance concrete is not a new material of construction.
somewhat disconcerting to many .We had high strength concrete, hyperplasticiser, and
superplasticisers, very reactive Pozzolana, and now high performance concrete. It is difficult to imagine any concrete being manufactured and used, which is not intended to perform to the extent; high performance concrete is not a new material of construction.
Maturity Concept of Concrete
Maturity Concept of Concrete
(if file is not opening then rename file to maturity.pptx)
Download :
http://www.ziddu.com/download/19766323/maturity.ppt.html
(if file is not opening then rename file to maturity.pptx)
Download :
http://www.ziddu.com/download/19766323/maturity.ppt.html
Monday, 25 June 2012
Abstract on Millau Viaduct Bridge
The below attachment is the abstract of millau viaduct bridge
An engineering and architectural marvel! Just imagine it took them just 39 months to complete such a difficult feat.
Can't remember off hand, but there was a really good documentary on the construction of it on Discovery or TLC a month or so ago. It's located in southern France, and is the highest bridge in the world.
It is a truly amazing piece of engineering, especially considering the method used to span the distance between the piers. Between the red towers you see in the photo were removed following completion of the bridge. Be sure to maximize your screen for this. They haven't printed enough money to pay me to drive across this bridge!!
An engineering and architectural marvel! Just imagine it took them just 39 months to complete such a difficult feat.
Can't remember off hand, but there was a really good documentary on the construction of it on Discovery or TLC a month or so ago. It's located in southern France, and is the highest bridge in the world.
It is a truly amazing piece of engineering, especially considering the method used to span the distance between the piers. Between the red towers you see in the photo were removed following completion of the bridge. Be sure to maximize your screen for this. They haven't printed enough money to pay me to drive across this bridge!!
Green Buildings [doc]
Presentation on Green Buildings.
Download :
http://www.ziddu.com/download/19758177/ABSTRACT.doc.html
Download :
http://www.ziddu.com/download/19758177/ABSTRACT.doc.html
Instant Concrete Road Repair Solution
The Durability of road structures depends on the quality of its
maintenance & minor renovations. Maintenance keeps the roadway safe,
provides good driving conditions & prolongs the life of the
pavement, thus protecting the road investment.
Currently in India more than 2000 km of concrete road is in the operation since last few years. Most of the projects completed by NHAI, MSRDC and other state government authorities.
Though the quality & procedural aspects, specifications / guidelines clearly mentions in IRC, MoRTH, but still we observes that various minor cracks, potholes and joints edge spalling in the PQC due to various factors which requires maintenance.
Maintenance includes the prompt sealing of cracks & filling of potholes to prevent water entering through the surface.
Repairs and rehabilitation of concrete roads are required to have a smooth riding quality as well as avoid inconvenience causing to the vehicles.
We need to have a durable repair products to avoid of cost of various factors like :
a) Diverting the traffic for repairs
b) Inconvenience to the traffic
c) Repeatedly cost of repairs by using conventional methods.
Currently in India more than 2000 km of concrete road is in the operation since last few years. Most of the projects completed by NHAI, MSRDC and other state government authorities.
Though the quality & procedural aspects, specifications / guidelines clearly mentions in IRC, MoRTH, but still we observes that various minor cracks, potholes and joints edge spalling in the PQC due to various factors which requires maintenance.
Maintenance includes the prompt sealing of cracks & filling of potholes to prevent water entering through the surface.
Repairs and rehabilitation of concrete roads are required to have a smooth riding quality as well as avoid inconvenience causing to the vehicles.
We need to have a durable repair products to avoid of cost of various factors like :
a) Diverting the traffic for repairs
b) Inconvenience to the traffic
c) Repeatedly cost of repairs by using conventional methods.
Tuesday, 12 June 2012
Circular curves in Engineering Survey
In the vertical design, intersecting gradients are connected by curves in the vertical plane.
Circular curves are used to join intersecting straight lines (or tangents). Circular curves are assumed to be concave. Horizontal circular curves are used to transition the change in alignment at angle points in the tangent (straight) portions of alignments. An angle point is called a point of intersection or PI station; and, the change in alignment is defined by a deflection angle, Δ.
Types of Circular Curves are:
- Simple Curve
- Compound Curves
- Broken Back Curves
- Reverse Curves
A. Radius of a circular curve
The Radius is the distance from the center of the curve to any point on the circular curve.B. Direction of a circular curve
The Direction of a Circular Curve is defined as the direction the curve tends, as stationing along the curve increases. Can be expressed as: Left, Right, North, East, South, West, free text
C. Central angle of a circular curve
The Central Angle of a Circular Curve is the angle at the center of radius of a circular arc included between the radii, passing through the beginning and ending of the arc.
D. Long Chord Length
The Long Chord Length is the straight line distance connecting the beginning of the curve and the end of the curve.
E. Degree of Curvature
The Degree of Curve is defined as the angle subtended by an arc whose length is 100 ft. A Radian is the angle subtended by an arc whose length equals the length of the Radius, or
57° 17’ 44.8” , or 57.295779513°.
i. Curvature can be expressed in two ways, By:
- Stating the length of the chord of the curve
- Stating the radius of curvature
F. Laying out Circular Curves
-
Select tangents, and general curves making sure you meet minimum radius criteria
-
Select specific curve radii/spiral and calculate
important points (see lab) using formula or table (those needed for
design, plans, and lab requirements)
-
Station alignment (as curves are encountered)
-
Determine super and runoff for curves and put in table (see next lecture for def.)
-
Add information to plans
G. Sight Distance of a circular curve
Sight line is a chord of the circular curve. Sight Distance is curve length measured along centerline of inside lane. Sight distance can be the controlling aspect of horizontal curve design where obstructions are present near the inside of the curve. To determine the actual sight distance that you have provided, you need to consider that the driver can only see the portion of the roadway ahead that is not hidden by the obstruction. In addition, at the instant the driver is in a position to see a hazard in the roadway ahead, there should be a length of roadway between the vehicle and the hazard that is greater than or equal to the stopping sight distance
Curves should be designed with their radius greater than Rmin. If Rmin cannot provided enough lateral clearance to an obstruction.
Monday, 11 June 2012
Saturday, 9 June 2012
Gypsum Plaster- An Overview
In recent years, the construction sector has witnessed a number of new trends, technology advancements and innovations across applications, all aimed at making construction faster and delivering higher performance.
However, very few would have imagined that the substitute for the generations old method of sand cement surface plastering will be an even older method of plastering i.e. gypsum plastering. Gypsum has proved to be a miraculous material aiding interior construction. Gypsum surface plaster is one form that has caught the attention on the sector and is growing in popularity.
The oldest example of usage of gypsum as an internal plaster is found in the Pyramids of Giza in Egypt which were lined with gypsum stucco plaster centuries ago and are still intact, which is proof of the durability & performance of this product.
- What is Gypsum?
Construction Techniques
Production of concrete requires meticulous care at every stage. The
ingredients of good and bad concrete are same but good rules are not
Observed it may become bad.
Manufacturing of concrete includes the following stages
1. Batching
2. Mixing
3. Transporting
4. Placing
5. Compacting
6. Curing
7. Finishing
Importance of Irrigation
Definition
– “the supply of water to crops and landscaping plants by artificial means”
• Estimates of magnitude
– world-wide: 544 million acres
• (17% of land 1/3 of food production)
Purpose
• Raise a crop where nothing would grow otherwise (e.g., desert areas)
• Grow a more profitable crop (e.g., alfalfa vs. wheat)
• Increase the yield and/or quality of a given crop (e.g., fruit)
• Increase the aesthetic value of a landscape (e.g., turf, ornamentals)
– “the supply of water to crops and landscaping plants by artificial means”
• Estimates of magnitude
– world-wide: 544 million acres
• (17% of land 1/3 of food production)
Purpose
• Raise a crop where nothing would grow otherwise (e.g., desert areas)
• Grow a more profitable crop (e.g., alfalfa vs. wheat)
• Increase the yield and/or quality of a given crop (e.g., fruit)
• Increase the aesthetic value of a landscape (e.g., turf, ornamentals)
Structural Analysis
Members of structure deform due to external loads. The minimum number of
parameters required to uniquely describe the deformed shape of
structure is called “Degree of Freedom”. Displacements and
rotations at various points in structure are the parameters considered
in describing the deformed shape of a structure. In framed structure the
deformation at joints is first computed and then shape of deformed
structure. Deformation at intermediate points on the structure is
expressed in terms of end deformations. At supports the deformations
corresponding to a reaction is zero. For example hinged support of a
two dimensional system permits only rotation and translation along x and
y directions are zero.
Thursday, 7 June 2012
Design of the RCC Concrete Plants
Automatic Feeding System
Dumpers or belts convey the coarse aggregates via feeding hopper and conveyor belts to the stock pile. From the stock pile the particular fractions are conveyed via conveying troughs onto the corresponding belts. Each specific grain size can be batched onto each belt. With these two belts the coarse aggregates are conveyed to the 150 m long cooling gallery.
The fine aggregates as well are conveyed via feeding hopper and belt to the stock pile. The fine aggregates are conveyed to the inline silo without being chilled.
Cooling of Coarse Aggregates
Water chillers produce large quantities of cold water at + 4 degree C. The cold water is sprayed via nozzles across the total length of the cooling gallery onto the rock grains greater than 5 mm. At the end of the cooling gallery we obtain a temperature of the graining of approx. + 7 degree C. The aggregates are dewatered at selected points. At the end of the cooling gallery dewatering screens dewater the material to a residual moisture of 2 %. This method is very effective because much water is accumulated in the coarse grain.
Water is then led into the sedimentation tank to have the flushed floating particles deposited. The cleaned water is now cooled again and added to the circuit.
Alternatively for other projects and according to the requirements the cooling of the aggregates can be effected in an aggregate cooling silo.
The particular cooled components are conveyed into separate compartments of the insulated inline silos. The sizes of the separate compartments of the inline silo have been dimensioned to take up the total capacity of the belt. It is important for safety requirements that each component can be conveyed via each belt into each compartment of the inline silo.
Production and Handling of Ice Flakes
Two containerized flake ice plants produce 24 hours continuously flake ice into both ice storage tanks. The requested ice is conveyed with screws from these ice storage tanks into the day tanks which provide the ice to the particular ice weighers for weighing. The requested ice can be supplied from each day tank into each of the 4 ice weighers.
Water Chillers
The water chillers have been containerized as well. They provide the cooling of the aggregates, the ice treatment and the requested mixing water for the concrete.
Storage and Transportation of Cementitious Materials
To guarantee a sufficient quantity of cement and pozzolan on site all in all 10 x 1000 t storage silos have been installed. Pneumatic cement blower systems provide the corresponding service silos – per plant 2 silos à 150 t – from these storage silos.
Concrete Batching and Concrete Production
To obtain the requested nominal plant capacity of 500 m³/h compacted concrete 2 twin plants with a total of 4 x3 m³ twin shaft mixers have been installed.
Each twin plant is equipped with an inline silo of 4 x 100 m³. From this inline silo the particular fractions are -according to the recipe – weighed additively on the weighing belt. All materials, such as aggregates, cement, pozzolan, admixtures, cold water and ice are weighed and conveyed into the mixer.
For a homogeneous mixing of the concrete Liebherr exclusively uses twin shaft mixers from internal production. These mixers stand out for short mixing times and short discharge times. Due to special wear plates these mixers have a very long durability. The maintenance works are reduced due to a central lubrication system.
Concrete Delivery System
Below each high performance mixer an especially developed rotary system has been installed which allows feeding the high speed belt and the dumpers as well which are filled from 2 mixers at the same time. The high speed belt has been equipped with a discharge point to provide further tipping of dumpers.
CAUSES OF FAILURE OF FOUNDATIONS IN BUILDINGS
Causes of Foundation Failure in Buildings
Foundation failure can be attributed to several things. Most commonly foundation failure is caused by the movement of expansive and highly plastic soils beneath different sections of the foundation footings. This movement can be in the form of shrinkage, which causes settlement, or expansion, which causes heave. When dry conditions prevail, soils consistently lose moisture and shrink. When moisture levels are high, soils swell. Regardless of the nature of the movement, it will most likely manifest itself in the form of visible cracks in the foundation walls, exterior brick walls, or interior Sheetrock or plaster walls. Officially, any structure movement is known as differential settlement.
foundation-failure-causes
In addition to expansive soils, subsurface peat, which has a low bearing capacity and deteriorates over time, can also cause differential settlement. Other soil types such as sand and silt also have lower than required bearing capacities.
Poor drainage from yard run-off and gutter downspouts discharging at the base of the foundation are among other causes. Excess moisture around the foundation can cause the soils to become over-saturated and lose “bearing pressure,” or the strength to support weight. When this happens, structures “settle” or sink into the ground.
If soil and water control problems weren’t bad enough, there is also the issue of transpiration. Transpiration is a fancy word for the process of trees and large plantings absorbing the water from the soils beneath and around your home. During an active season, roots extending beneath and around the footings of the house can remove moisture from the soil, causing it to become desiccated. Again, where expansive soils exist this removal of moisture will cause soil shrinkage and settlement.
Plumbing leaks are another major contributor to foundation settlement. Inundating the foundation with water from your home’s pipes will cause foundation failure, as would poor drainage on the outside.
Poor construction sometimes causes settlement in homes, but only rarely.
Foundation failure can be attributed to several things. Most commonly foundation failure is caused by the movement of expansive and highly plastic soils beneath different sections of the foundation footings. This movement can be in the form of shrinkage, which causes settlement, or expansion, which causes heave. When dry conditions prevail, soils consistently lose moisture and shrink. When moisture levels are high, soils swell. Regardless of the nature of the movement, it will most likely manifest itself in the form of visible cracks in the foundation walls, exterior brick walls, or interior Sheetrock or plaster walls. Officially, any structure movement is known as differential settlement.
foundation-failure-causes
In addition to expansive soils, subsurface peat, which has a low bearing capacity and deteriorates over time, can also cause differential settlement. Other soil types such as sand and silt also have lower than required bearing capacities.
Poor drainage from yard run-off and gutter downspouts discharging at the base of the foundation are among other causes. Excess moisture around the foundation can cause the soils to become over-saturated and lose “bearing pressure,” or the strength to support weight. When this happens, structures “settle” or sink into the ground.
If soil and water control problems weren’t bad enough, there is also the issue of transpiration. Transpiration is a fancy word for the process of trees and large plantings absorbing the water from the soils beneath and around your home. During an active season, roots extending beneath and around the footings of the house can remove moisture from the soil, causing it to become desiccated. Again, where expansive soils exist this removal of moisture will cause soil shrinkage and settlement.
Plumbing leaks are another major contributor to foundation settlement. Inundating the foundation with water from your home’s pipes will cause foundation failure, as would poor drainage on the outside.
Poor construction sometimes causes settlement in homes, but only rarely.
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