This document provides information on concrete mix design and testing concrete cubes. It discusses determining the target mean strength of concrete, properties and types of aggregates, and how to calculate the aggregate to cement ratio and water to cement ratio. It also outlines the process for sampling concrete, filling and compacting concrete cubes, curing the cubes, and testing them to determine compressive strength. The compressive strength tests help evaluate the quality of the concrete mix and its constituents. Maintaining proper procedures at each stage of mixing, placing, and curing the concrete is important for achieving the desired compressive strength.
This presentation contains IS Concrete mix design method and Basics of Design mix of concrete.It conveys; Objectives of Mix Design ;Grades of Concrete; Nominal Mix and Design Mix; Factors affecting Choice of Mix Design; Methods of Concrete Mix Design; IS Method Of Design.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required, strength, durability, and workability as economically as possible, is termed the concrete mix design.
This presentation contains IS Concrete mix design method and Basics of Design mix of concrete.It conveys; Objectives of Mix Design ;Grades of Concrete; Nominal Mix and Design Mix; Factors affecting Choice of Mix Design; Methods of Concrete Mix Design; IS Method Of Design.
MEANING OF MIX DESIGN
GRADE OF CONCRETE.
FACTORS INFLUCING THE CHOICE OF MIX DESIGN.
MATHODS OF CONCRETE MIX DESIGN
MIX DESIGN BY INDIAN STANDARD METHOD.
The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required, strength, durability, and workability as economically as possible, is termed the concrete mix design.
As a project in undergraduate college, we decided to explore soil and ways to reinforce using plastic fibers. Our study included Geo synthetic meshes as well as chemical stabilizers. Our scope of study study was finalized to be Waste Plastic Fiber Reinforced soil, as plastic was being used experimentally in small projects while waste plastic is easily available.
Concrete Mix design with the recommendation of IS10262:2009. Also discussed the differences between the IS10262:2009 and IS10262:1982.
The major content of presentation are:
Scope
Introduction
Factors affected mix design
Mix Design
Differences b/w IS10262:1982 and 10262:2009
Exercise
As a project in undergraduate college, we decided to explore soil and ways to reinforce using plastic fibers. Our study included Geo synthetic meshes as well as chemical stabilizers. Our scope of study study was finalized to be Waste Plastic Fiber Reinforced soil, as plastic was being used experimentally in small projects while waste plastic is easily available.
Concrete Mix design with the recommendation of IS10262:2009. Also discussed the differences between the IS10262:2009 and IS10262:1982.
The major content of presentation are:
Scope
Introduction
Factors affected mix design
Mix Design
Differences b/w IS10262:1982 and 10262:2009
Exercise
A UHPC (ultra high performance concrete) presentation projects.Nolan Mayrhofer
UHPC presentation featuring select international Ductal projects. This is an in depth look at the types of architectural projects UHPC is best suited for.
Development of mix design for high strength Concrete with AdmixturesIOSR Journals
This paper presents the result of mix design developed for high strength concrete with silica fume
and High range water reducing admixture (HRWR). It involves the process of determining experimentally the
most suitable concrete mixes in order to achieve the targeted mean strength. In this research work 53 grade
ordinary Portland cement, the locally available river sand, 10 mm graded coarse aggregate were selected based
on ASTM C 127 standard for determining the relative quantities and proportions for the grade of concrete M60.
For this design ACI 211.4R-93 guidelines were followed. Totally Five mixes were designed one mix was treated
as basic mix with HRWR - 0.5% without silica fume, Four mixes were designed with Micro silica quantities
varied from 5 to 9 percent weight of cementitious materials and HRWR varies between 0.6% to 0.9% with
increment of 0.1% . Each mix 2 numbers of 150mm x 300 mm cylinders were cast then kept in curing tank after
24 hours of time period. After 28 days of curing the specimens were tested and the appropriate mix proportions
were obtained.
THIS PRESENTATION IS MAINLY OCCUPIED IN CE 6002 CONCRETE TECHNOLOGY UNIT NO.03......
-------FOR CIVIL ENGINEERING STUDENTS IN 2013 REGULATION =-------------------------
The Effect of Rise Husk Ash on Strength and Permeability of ConcreteAkshay D Nicator
HA, produced after burning of Rice husks (RH) has high reactivity and pozzolanic property. Indian Standard code of practice for plain and reinforced concrete, IS 456- 2000, recommends use of RHA in concrete but does not specify quantities.
Overview of Soil Stabilization :Cement / Lime :PPTAniket Pateriya
Soil-cement is frequently used as a construction material for pipe bedding, slope protection, and road construction as a sub-base layer reinforcing and protecting the subgrade. It has good compressive and shear strength, but is brittle and has low tensile strength, so it is prone to forming cracks.
Lime can be used to treat soils to varying degrees, depending upon the objective. The least amount of treatment is used to dry and temporarily modify soils. Such treatment produces a working platform for construction or temporary roads. A greater degree of treatment supported by testing, design, and proper construction techniques--produces permanent structural stabilization of soils.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
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Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
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Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
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COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
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The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
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Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
2. CONTENTS
CONCRETE MIX DESIGN
Introduction
Specification of concrete
Target mean strength of concrete
Aggregates
Determination of aggregate to cement ratio (A/C)
Correction for specific gravity
Correction for flakiness
Determination of concrete density
Cement content in concrete mix
Concrete mix by Weight
Total aggregate content
Determination of W/C
2
3. INTRODUCTION :
+ + +/- Additives
=Concrete +
CONCRETE MIX DEPENDS ON :
Workability
5 categories:
•Very high
•High
•Medium
•Low
•Very low
Strength
Finished surface
Consistency
Durability = Quality of material, environmental effect
Compactibility
Mobility
Stability or cohesiveness
Water content in concrete mix
Nature of aggregate particles
(shape, surface, porosity)
3
4. SPECIFICATION OF CONCRETE :
Environmental
effect
Mixing Compacting Batching Transporting Placing Cement
content
Strength Water - cement ratio Aggregate - cement ratio
Fly ash
GGBFS
TARGET MEAN STRENGTH OF CONCRETE :
New site
• No old track record is available
• Requires at least 30 test strength results of
same grade of concrete
Old site
• Old track records
is available
Methods – determined by following situation
4
5. Formula to calculate TARGET MEAN STRENGTH (Fm) –
Fm = Fck + t X s
Where,
Fm = target mean strength
Fck = strength of concrete
( Strength achieved in 28 days )
t = constant
( probability of no. Of results fall below Fck )
s = standard deviation
( 30 hourly test results collected & tested daily using all 24hr samples mixed together )
AGGREGATES
Types --------------------------Types --------------------------
Coarse Aggregates
Particles greater than
4.75mm.
E.g.- Gravel and
crushed rock
Downgraded Coarse Aggregates
Size may be either 40mm CAN and
20mm CA1 or 30mm CAN and
15mm CA1
Fine Aggregates
Particles passing
through 9.5mm sieve
E.g. - Natural sand
5
6. Properties ---Properties ---
Physical
• Texture
• Structure
• Composition
Chemical
• Solubility
• Reactivity
• Weathering
resistance
S.
No.
Properties of
Aggregate
Influence on Concrete
property
1. Porosity Strength / absorption
2. Chemical stability Durability
3. Surface texture Bond grip
4. Shape, size Water demand, strength
Shape of Aggregates ---Shape of Aggregates ---
Rounded gravel Irregular gravel Crushed rock
6
7. Fineness of Aggregates :Fineness of Aggregates :
Influence the water demand of concrete mix
or strength.
Classified in 4 zones –----Classified in 4 zones –----
Zone 1
Coarse sand
Zone 2
Normal sand
Zone 3
Fine sand
Zone 4
Very Fine sand
The selection of proportion of FA is given
by Department of Environment (DOE), UK
Maximum size of the AggregatesMaximum size of the Aggregates
(MAS) :(MAS) :
Mostly MAS is 10mm, 20mm or 40mm
is used.
For massive work, MAS is 150mm or
above is used.
Limitation of MAS :
Minimum dimension of concrete section to be cast is < 4 X MAS
7
Zone 1
Zone
2
Zone 3
Zone 4
8. Determination of Aggregate to Cement Ratio (A/C):
A/C ratio can be calculated if following factors are known or determined:
Shape of the aggregate
Maximum aggregate size (10mm,20mm,40mm)
Zone of aggregates (1,2,3,4)
Degree of workability
Water-to-cement ratio
If concrete ingredients consist of coarse crushed and natural fine aggregates then A/C is
adjusted as follows :
Determine A/C for crushed aggregates for the MAS fixed for the Mix (Say Aca)
Determine A/C for rounded or irregular gravel aggregates for MAS fixed for the Mix
(Say Afa)
Calculate A/C of the concrete mix (Say A’) as per formula
A’ = Aca (%of CA1+%of CA2) + Afa (%of FA1)
100 100
Where,
Aca = Actual coarse aggregate
Afa = Actual fine aggregate
FA1 = Fine aggregate (zone 1)
CA1 = Coarse aggregate (zone 1)
CA2 = Coarse aggregate (zone 2)
8
9. Correction for Specific Gravity:
The specific gravity (relative density) of an aggregate is the ratio of its weight to the
weight of an equal volume of water displaced by the aggregates
Ranges between 2.6 to 2.9
Lower or higher specific gravity changes A/C ratio ,hence needs correction:
A”= A’ca (actual specific gravity) + A’fa (actual specific gravity)
2.5 2.6
A”= A”ca + A”fa
Where,
A” = Corrected A/C
A’ca = Actual specific gravity of coarse aggregate
A’fa = Actual specific gravity of fine aggregate
A”ca = Corrected specific gravity of coarse aggregate
A”fa = Corrected specific gravity of fine aggregate
9
10. Correction for Flakiness:
The aggregate is said to be flaky when its least dimension is less than 3/5th
(or 60%) of
its mean dimension
Mean dimension, is the average size through which the particles pass, and the sieve
size on which these are retained
e.g., mean size of the particles passing through 25 mm sieve and retained on 20 mm
sieve is (20+25)/2=22.5 mm
If the least dimension is less than 3/5 x (22.5) = 13.5 mm, then the material is classified
as flaky
Flaky or angular aggregates have greater surface area -to-weight ratio therefore, it
is necessary to apply correction factor for flakiness
A/C ratio = A”x 0.95
A” = Specific gravity
If workability is correct ,A/C ratio is correct
Workability is more , increase A/C ratio
Workability is less , reduce A/C ratio
10
11. Density of Concrete (Kg/CuM)
Concrete density can be worked out by actually weighing the standard concrete cubes
Volume of standard concrete cube = 3.375 x 103
cum
Concrete Density = Average Weight of the cube (Kg)
Volume of the cube (cum)
Determination of concrete density:
Cement content in concrete mix:
Concrete mix by weight:
Total aggregate content:
CEMENT Content (Kg/CuM) =
1+ A / C + W / C
WATER Content (Kg/CuM) = W / C X Cement Content (Kg/CuM)
AGREEGATE Content (Kg/M) = A / C X Cement Content (Kg/CuM)
11
12. Determination of W/C:
• W/C determine for compressive strength 33 N/mm2 is 0.52.
• Durability condition specifies Max. W/C = 0.55.
• W/C determine for compressive strength 38 N/mm2 is 0.48.
• Durability condition specifies Max. W/C = 0.45 and corresponding A/C = 4.60 .
1.If workability is < targeted, A/C to be reduced and fresh trial taken.
2.If workability is > targeted, A/C can be increased provided durability criteria of Min.
Cement and Maximum W/C are not violated.
3.If cohesiveness is <, proportion of fine aggregates and / or cement can be increased.
CONCLUSIONCONCLUSION
• The Engineer will have to exercise at times, his judgement based on his experience &
skill for finalising the most economic concrete mix.
• The systematic working of concrete mix design improves the quality & performance of
concrete structures.
• It also helps in economic usage a cement as well as gives overall economy.
• From this information Engineers gets help to work out correctly the concrete mix design
instead of using conventional nominal concrete mixes.
12
14. Age to strength relation – chemical compositions and fineness
Higher early strength
content of Tricalcium cilicate > Dicalcium cilicate
Finer ground cement > coarse ground cement
CONTENTS
CONCRETE TEST CUBES
Introduction
Parameters affecting compressive strength
Sampling
Equipments
Procedure for filling and compacting
Identification, curing and testing concrete cubes
Requirement of compression testing machine
Acceptance criteria for compressive strength
Modes of failures
Conclusion 14
15. Age to strength relation – chemical compositions and fineness
Higher early strength
content of Tricalcium cilicate > Dicalcium cilicate
Finer ground cement > coarse ground cement
Introduction
Concrete strength are generally specified by compressive
strengths and the structural design is worked out on that basis.
Exact information
of compressive strength
of concrete depends
on quality control
Parameters affecting
compressive strength
•Cement (quality and grade)
•Water (water-cement ratio)
•Cement storage and transportation
•Cement packaging
•Aggregates
•Concrete workability
•Concrete placement
•Concrete compaction
•Curing of concrete
15
16. 1.65
Higher early strength
Cement
Early strength of cement
Content of Tricalcium silicate (C3S)Content of Tricalcium silicate (C3S)
Finer textureFiner texture
Content of Dicalcium silicate (C2S)Content of Dicalcium silicate (C2S)
Coarse textureCoarse texture
Variation in compressive strength
Supply from
different units
Supply from
different units
Supply from
different brands
Supply from
different brands
Variation of Compressive strength
from the same unit by each set.
Variation of Compressive strength
from the same unit by each set.
SolutionObtain monthly standard
deviation factor
Obtain monthly standard
deviation factor
Obtain co-efficient of
variation
Obtain co-efficient of
variation
Grade of cementGrade of cement
average
compressive
strength for a month
average
compressive
strength for a month
Standard deviation
for the same month
Standard deviation
for the same month
1.65
Experimenting the results by making sample of
cement cube and apply the following formula
Experimenting the results by making sample of
cement cube and apply the following formula
Parameters affecting compressive
strength
16
17. Water
strength of cement Lower the water to cement ratio higher the strength
and durability
Lower the water to cement ratio higher the strength
and durability
Affects in lower w/c ratio as well as higher grade of cementAffects in lower w/c ratio as well as higher grade of cement
Solution – accurately batch water so that it should not exceed much
Cement storage & transportation
Loss in strength In contact with moisture or waterIn contact with moisture or water
Solution – store carefully in water tight condition
must arrive on site with minimum possible time and less handlings
Cement packing
Maintaining strength
Preserve in longer time under same climatic
exposure
Preserve in longer time under same climatic
exposure
Solution – use porous material for packing bags
17
18. Aggregate
size Larger the size less cement water pasteLarger the size less cement water paste
shape Rounded aggregates, lesser surface area, so less c/w pasteRounded aggregates, lesser surface area, so less c/w paste
grading Lesser finer particles , Coarse finer aggregate mixLesser finer particles , Coarse finer aggregate mix
porosit
y
Porous aggregate may crush after adding load, so be with
solids
Porous aggregate may crush after adding load, so be with
solids
Concrete workability
Don't add excess of water,
it will loose its strength
Don't add excess of water,
it will loose its strength
Concrete transportation
concrete cubes are taken from batching plant.
Should not get segregate as it forms honeycomb like porous cavities.
1% trapped air reduce 6% strength
concrete cubes are taken from batching plant.
Should not get segregate as it forms honeycomb like porous cavities.
1% trapped air reduce 6% strength
Concrete compaction
Entrapped air is driven out
by compaction using
vibration techniques
Entrapped air is driven out
by compaction using
vibration techniques
18
19. Concrete curing
Due to inadequate water for
curing concrete surface cracks
and looses strength
So, its essential to cure concrete
cubes and keep moist up to 28
days.
Change in temperature affects
compressive strength, so cure
with 27 degree +/-
Due to inadequate water for
curing concrete surface cracks
and looses strength
So, its essential to cure concrete
cubes and keep moist up to 28
days.
Change in temperature affects
compressive strength, so cure
with 27 degree +/-
Compressive strength = potential energyCompressive strength = potential energy
This test helps
To determine
This test helps
To determine
Variations in concrete gradeVariations in concrete grade
All proportions of various materials in concrete mixAll proportions of various materials in concrete mix
Quality controlQuality control
Rate of gain of strength & time to removal of formworkRate of gain of strength & time to removal of formwork
Purpose of the test
Note: cube strength does not necessarily match with the final concrete structureNote: cube strength does not necessarily match with the final concrete structure
19
20. Sampling
Randomly taken, no extra dry or extra wet concreteRandomly taken, no extra dry or extra wet concrete
Fix for each
day
Fix for each
day
Numbers of concrete mixtures on siteNumbers of concrete mixtures on site
After specific deliveries of materialsAfter specific deliveries of materials
Specifications of different materialsSpecifications of different materials
Quantum of concreteQuantum of concrete
Concrete is being discharged from conventional or transit mixtureConcrete is being discharged from conventional or transit mixture
Min. Frequency of each grade of concreteMin. Frequency of each grade of concrete
Concrete is Poured in four equal incrementsConcrete is Poured in four equal increments
Some by buckets or some by sampling scoop & thoroughly mixedSome by buckets or some by sampling scoop & thoroughly mixed
Quantity per cube – 3kg. (for 100mm cube) & 10kg. (for 150mm cube)Quantity per cube – 3kg. (for 100mm cube) & 10kg. (for 150mm cube)
If concrete is taken from truck or dumper, its necessary to take samples from six
possible locations.
If concrete is taken from truck or dumper, its necessary to take samples from six
possible locations.
After remixing cube mould should be filled up immediatelyAfter remixing cube mould should be filled up immediately
20
21. Equipments
Cube mouldsCube moulds
Only steel or cast iron
Made up of three parts
1.two side flanges
2.base plate
3.nut bolts
Inside faced must be planed and machine
finished
All internal angles has to be accurate
Edges and joints must be cleaned
Surfaces should be coated by mould oil
Prevent mould from rusting
All parts should be bolted and then stored
in close room
Tamping rodTamping rod
Steel bar of 16mm dia.
600 mm length
Bullet head
spannersspanners
Mould oilMould oil
scrappersscrappers
Big size scoopBig size scoop
Small size scoopSmall size scoop
A levelling floatA levelling float
Wheel barrowWheel barrow
Cleaning ragsCleaning rags
Non absorbent trayNon absorbent tray
Sharp marking scrapperSharp marking scrapper
Curing tankCuring tank
Polythene sheetingPolythene sheeting
21
22. Process for filling & compacting cube
mould
must be done into three layers
each app. 50mm
Must be placed using scoop
each layer is compacted using tamping rod
needs 35 stroke for 150mm &
25 stroke for 100mm
surface level should be planed
No air gaps in between or
scratches on surface
22
23. Process for identification , curing &
testing
On the surface level some
identification mark, number and
date has to be scratched and
same noted on paper
after removal from mould it should
immediately covered with damp jute
Transfer to a room having
humidity90% and temperature 27^
Keep the cube in curing pond of
clean water for 28 days
automatic compression
machine is better than manual
load application
Machine has a control on rate of
loading, we can apply various
loading while testing its strength
23
24. Precautions need to be taken while
testing
allow skilled workers only
Fresh water within 7 days only used for curing pond
Cubes has to be deep completely
Storage space has to be without any vibrations
Temperature control from 22 to 30 ^c.
There should not be loss in moisture while travelling from site to testing lab.
A float should be used to push the excess concrete after pouring third layer.
If the mix is too wet, allow water to drained out from mould.
24
25. Requirement of compression testing
machine must be accurate
Well calibrated, well certified
Having capacity to crush cube
TOP PLATEN :
Harden and smooth faces
Fitted on cylinder concentric
with central point
BOTTOM PLATEN :
Plain finished
Rigidly fixed on bearing block
Size more than cube size
Load applying rod
Concrete cube placing space
Selection of machine depends
on size of cube and load
application
25
26. Acceptance criteria for compressive
strength
Note the reading by applying
different loads from machine till the
cube crashes
Compressive strength should not be
less than the characteristic value
26
27. Modes of failures
USUAL FAILURES:
Equal cracking on all four sides
No damage to top and bottom faces
Cracks are vertical zigzag pattern
vertical faces breaks away leaving one
pyramid between
UNUSUAL FAILURES:
Crushed only at one side
Tensile or horizontal cracks only at one side
This indicates lower compressive strength
Reasons
Defects in machine
Faulty manual operation
Faulty casting of cube
Improper curing 27