Rapid hardening cement (RHC) is a type of cement that achieves higher early strength development compared to ordinary Portland cement (OPC). It's formulated to set and harden rapidly, often within a few hours, allowing for faster construction processes. Here's an overview of its characteristics and uses:
Composition: Rapid hardening cement typically contains a higher proportion of tri-calcium silicate (C3S) and finer particles compared to OPC. These characteristics contribute to the rapid hydration and strength gain.
Setting Time: RHC has a shorter setting time compared to OPC. While OPC may take several hours to set, RHC can set in as little as a few minutes to a few hours, depending on the specific formulation and environmental conditions.
Early Strength Development: One of the primary advantages of RHC is its ability to achieve high early strength. This allows for quick demolding of concrete elements, early removal of formwork, and faster construction schedules.
Applications:
Emergency Repairs: RHC is often used for emergency repairs, where quick strength gain is essential to minimize downtime.
Cold Weather Concreting: In cold weather conditions, where low temperatures can slow down the hydration process, RHC can be used to accelerate strength development.
Pre-cast Concrete: RHC is commonly used in pre-cast concrete applications where fast turnaround times are required.
Highway Repairs: For rapid repairs of roads and highways, RHC can be advantageous due to its quick-setting properties.
Limitations: While RHC offers benefits in terms of early strength development and faster construction, it may have lower ultimate strength compared to OPC. Therefore, it's essential to consider the specific requirements of the project and balance the need for early strength gain with long-term durability.
Overall, rapid hardening cement is a valuable material in construction projects where time is of the essence, allowing for efficient and timely completion of tasks.
1. ANALYTICAL INVESTIGATION OF STRUCTURAL
BEHAVIOR OF REINFORCED CONCRETE COLUMN
USING DIAMOND TIE CONFIGURATION UNDER
ELEVATED TEMPERATURES
Under The Supervision of
ER. HIMMI GUPTA
(Assistant Professor)
Presented By
Sudesh Kumar
(171327-Modular)
Reg. No. 17-TTC-51
Department of Civil Engineering
National Institute of Technical Teachers Training and Research
Sector-26, Chandigarh - 160019
3. INTRODUCTION
GENERAL
A total of 2,500 citizens in India die per year as a result of
building fire occurrences . Fire causes thousands of deaths
and loss of property.
The fire incidents across the world have been seen which
results in the large amount of damage to reinforced
cement concrete framed structures.
Column being one of the most important loads bearing
member, the whole structure fails due to the failure of the
columns.
4. The increased use of cement in building design results in
the need to research the behavior of structures in
reinforced concrete.
Fire prevention and post fire maintenance should be taken
into account in the structure (retrofitting).
Many buildings suffer harm that cannot be repaired
because of inadequate fire laws.
5. FACTORS AFFECTING FIRE RESISTANCE
OF RCC COLUMNS
Aggregate Type
Concrete Grade
Lateral Strengthening
Longitudinal reinforcement
Intensity of fire
Intensity and type of load
Concrete cover
Column size
7. LITERATURE REVIEW
SR.
NO.
TITLE AUTHOR CONCLUSION
1. Permeability of
Heated Fiber-
Reinforced
High-Strength
Concrete
Sofren Leo
Suhaendi
et. Al
(2004)
In his investigation, the combination of
polypropylene fibres was found to be an
appropriate way to mitigate the process of
explosive spalling failure mechanism.
When high-resistance concrete is heated,
the runoff losses become more explosive.
The findings of a study on the residual
qualities of high strength fibre reinforced
concrete are presented in this publication..
Fiber length, fibre volume ratio, and fibre
content are only a few examples. Results
confirmed that explosive spalling might
take place inconsistently on HSC under
elevated temperature condition.
8. SR.
NO.
TITLE AUTHOR CONCLUSION
2. The Effect of
Elevated
Temperature
on Concrete
Materials and
Structures-A
Literature
Review
D. J. Naus
(2005)
this short study seeks to provide an
examination of the effect of high heats on
the analysis of RC elements. The study is
primarily focused on the performance of
reinforced concrete elements in designs of
new generation reactor concepts in which
the concrete may be exposed to long-term
steady-state temperatures in excess of the
present ASME Code limit of 65°C. The
longer the duration of heating before
testing, the larger the loss in strength.
However, the loss in strength stabilizes
after a period of isothermal exposure.
Also concrete specimens loaded during
heating loose less strength than unloaded
specimens.
9. SR.
NO.
TITLE AUTHOR CONCLUSION
3. Flexural
capacity of
singly
reinforced
beam with
150 MPa ultra
high-strength
concrete
Sungwoo
Shin et Al
(2010)
examine the hysteretic behavior of
ultrahigh-strength concrete tied columns
under stress to determine the effect of the
volumetric ratio of transverse
reinforcements on column deformability.
A reasonable method to enhance the
strength and ductility of tied columns is to
increase the amount of transverse
reinforcement confining the core concrete
and to take the transverse reinforcement
configuration into account when
designing the columns.
10. SR.
NO.
TITLE AUTHOR CONCLUSION
4. Comparative
Study of
Calculation
Models for
the Fire
Resistance of
Hollow Steel
Columns
Filled with
Concrete
Farid Fellah
et. Al (2011)
focuses on empty steel columns with
reinforced concrete linings, which are
often utilized in high-rise building
construction. In Europe and North
America, many investigations on the steel
reinforcement of these profiles have been
performed. Design engineers, on the other
hand, need more practical tools than
coders. Because the trial findings are
widely dispersed, developing such a
method would be difficult. His study looks
at three distinct methods, each of which is
based on a different procedure. We
compared the test results to the outcomes
of the three techniques. Each talent is
assessed for its potential, but it should
either be utilized with care or avoided
altogether.
11. SR.
NO.
TITLE AUTHOR CONCLUSION
5. Review on
storage
materials and
thermal
performance
enhancement
techniques for
high
temperature
phase change
thermal
storage
systems
Wasim
Khalik
(2012)
carried out the experimental and
numerical study on performance
characterization of high performance
concretes under fire conditions at both
material and structural level (specifically
columns). Results from fire resistance
tests show that plain HPC columns exhibit
lower fire resistance due to occurrence of
fire induced spalling and faster
degradation of strength. However,
presence of different fiber combinations in
HPC columns can significantly enhance
the fire resistance of the columns.
12. SR.
NO.
TITLE AUTHOR CONCLUSION
6. Analysis of
fire resistance
of concrete
with
polypropylen
e or steel
fibers
Ruben
Serrano and.
Al (2016)
Continuous development and enlargement
of structural elements is slowed by direct
contact to altitudes of up to 400 degrees
Celsius. By adding steel fibres or
polypropylene fibres into concrete, his
study seeks to address these issues.
Because it enhances both strength and fire
behavior and avoids cracking and
explosive concrete breaking, compression
crack test findings on cylindrical concrete
specimens indicate that polypropylene or
steel fibre reinforced concrete is a feasible
alternative to conventional concrete.
13. SR.
NO.
TITLE AUTHOR CONCLUSION
7. Effect of
temperature
on strength
and elastic
modulus of
high-strength
steel
Kodur
Venkatesh et
al. (2013)
studied that the high strength concrete
(HSC) columns exhibit lower fire
resistance, as compared to conventional
normal strength concrete columns, due to
occurrence of fire induced spalling and
faster degradation of strength and stiffness
properties of concrete with temperature.
Results show that HSC columns with 135o
bent ties exhibit higher fire resistance than
those HSC columns with 90o bent ties.
14. SR. NO. TITLE AUTHOR CONCLUSION
8. Performance
of insulated
FRP-
strengthened
concrete
flexural
members
under fire
conditions
Pratik Bhatt
and. Al
(2019)
develops a finite element (FE) based
numerical model in ABAQUS, to evaluate
the response of steel fiber reinforced
concrete (SFRC) columns under
combined effects of fire and structural
loading. Addition of steel fibers improves
the ductility, tensile strength and
toughness properties of concrete, and
thus, increases fire resistance of the HSC
column. Presence of the steel fibres in the
HSC columns can help to achieve up to
four hours of fire resistance.
15. SR. NO. TITLE AUTHOR CONCLUSION
9. Fire
Resistance of
Eccentrically
Loaded
Reinforced
Concrete
Columns
Shujaat
Hussain
Butch and
Umesh
Sharma
(2019)
observed that at ambient temperatures,
decrease in tie spacing is beneficial as it
increases moment capacity of the section
leading to better confinement. It is
observed that there is an improvement in
fire resistance by 150% for column with
diamond configuration as compared to
rectangular tie configuration with
crossties. it is observed that there was no
appreciable variation in the amount of
spalling for columns with diamond
configuration.
16. SR. NO. TITLE AUTHOR CONCLUSION
10. Experimental
Study of
Behavior of
Reinforced
Concrete
Columns with
added Steel
Fiber after
Fire Exposure
Mostafa
Abdel
Megied
Osman and.
Al (2020)
evaluates the improvement of the
behavior of reinforced concrete columns
strengthen by steel fibers after exposing
to fire. Ten R.C. columns with a circular
cross-section of 200 mm in Dia. and
1250 mm in Height with varying ratios of
steel fibers added in concrete mix
(0.50%, 1.0% and 1.50%), were
fabricated, then exposed to fire (Elevated
Temperature), and different methods of
fire resistance were loaded up to failure.
Results show that the strengthening with
steel fiber increased the load capacity and
stiffness of R.C. columns compared to
control specimens.
17. FINDINGS FROM LITERATURE
REVIEW
The inclusion of steel fibers in HSC columns may aid in
achieving up to 4 hours of fire resistance.
It was found that columns having diamond tie
configurations perform better in terms of fire resistance
than those having rectangular tie configurations including
crossties.
HSC columns with 135o bent ties are more resistant to fire
than with 90o bent ties.
18. Simple high performance concrete columns show
decreased fire resistance owing to the development of
fire-induced spalling and accelerated strength
deterioration. However, the inclusion of various fibre
mixes in high performance concrete columns may
substantially improve the columns' fire resistance.
Raising the longitudinal reinforcement proportion of RC
columns improves their fire resistance.
19. RESEARCH GAPS IDENTIFIED FROM
LITERATURE REVIEW
The fire resistance of RC columns are never been
explored for variation in tie diameter.
No comparison is carried out between experimental and
numerical study to clarify the behavior of reinforced
concrete columns with variation in tie diameter subjected
to fire.
20. 3D finite element (FE) modeling approach is never been
used to predict the mechanical response of various types of
the RC columns with variation in tie diameter of the
diamond tie configuration exposed to fire with sufficient
accuracy.
There is lack of data on high temperature properties
specific to different types of HPC (plain and with fibers).
Also, there is no methodology to account for the effect of
tie configuration on fire resistance of RC columns.
21. NEED AND SCOPE OF THE STUDY
The fire incidents across the world have been seen which
results in the large amount of damage to RCC framed
structures. Column being one of the most important load
bearing member losses strength during fire. The whole
structure fails due to the failure of the columns.
In this research, an attempt will be made to increase the
fire resistance of the RCC columns with the use of
diamond ties. The structures should be designed keeping
in consideration the fire preventive measures and the
repairs after fire. Many structures get damaged which not
remains in the condition of repair due to poor fire
regulations.
22. PROPOSED OBJECTIVES
The objective of the proposed thesis work is:
To determine the stress-strain relation for RC columns at
elevated temperature.
To study the response of normal strength concrete column,
high strength concrete column and steel fiber reinforced
concrete columns under fire conditions and compare their
structural behavior.
To analytically study the effect of use of diamond tie
configuration as lateral reinforcement in columns as
compared to lateral tie configuration on structural
behavior of the column using finite element analysis
approach.
23. RESEARCH METHODOLOGY
The following measures will be taken to carry out the
work:
Using the FEM software ANSYS, a 3D Finite Element
(FE) dependent computational model is created.
The ANSYS component is designed to follow the reaction
of the RC Columns through static elastic to fire failure
phase.
The study is conducted in small gradual times utilizing a
thermal-mechanical analysis technique sequentially
coupled.
24. Thermal load (fire exposed) is added to the column in
thermal analysis with the help of a given fire scenario
(duration ratios), whereby transversal temperature are
calculated.
The calculated pass heats are given for mechanical
analysis inputs whereby, in relation to the thermal
stresses, there are mechanical loading and constraints
added and column axial and side displacements and axial
potential are calculated.
The study takes into account the composite material's
physical and chemical thermal characteristics, as well as
deformations caused by insulating deformations.
25. The column's reaction to all potential failure limiting
states is compared at each point, and the period at which a
fault limiting condition is violated is taken by means of a
steel reinforcement (i.e., column failure time).
26. PROBLEM STATEMENT
All the columns were 3.81m long and had 305 mm X 305
mm square cross section. The columns were reinforced
with four steel bars of 25mm diameter in longitudinal
direction at a clear cover of 40 mm. The bars were tied
with lateral ties of 10 mm diameter at a spacing of 75 mm
in 650 mm length near the supports, and 145 mm spacing
in the middle of the column height. The HYSD500
should be checked in the ANSYS program for two legged
stirrups and diamond stirrups with a load of 1700 KN and
the thermal analysis should also be performed to verify
the impact of columns after temperature stresses.
27. RESULT AND DISCUSSION
MODELS PREPARED IN ANSYS
MODEL 1 COLUMN WITH NSC
MODEL 2 COLUMN WITH HSC
MODEL 3 COLUMN WITH SFRC
MODEL 4 COLUMN WITH DIAMOND STIRRUP NSC
MODEL 5 COLUMN WITH DIAMOND STIRRUP HSC
MODEL 6 COLUMN WITH DIAMOND STIRRUP SFRC
28. MODEL 1: COLUMN WITH NSC:
Fig 2: Total Deformation
NSC
Fig 3: Normal Stress
NSC
29. MODEL 2: COLUMN WITH HSC
Fig 4 : Strain Energy
HSC
Fig 5: Maximum
Principal Stress HSC
30. MODEL 3: COLUMN WITH SFRC
Fig 6: Shear Stress SFRC Fig 7: Equivalent Stress SFRC
31. MODEL 4: COLUMN WITH DIAMOND
STIRRUP NSC
Fig 8:Total Deformation
Diamond Stirrup NSC
Fig 9: Normal Stress
Diamond Stirrup NSC
32. MODEL 5: COLUMN WITH DIAMOND
STIRRUP HSC
Fig 10: Strain Energy
Diamond Stirrup HSC
Fig 11: Maximum Principal
Stress Diamond Stirrup HSC
35. Above graph shows the result for Total Deformation in mm for
columns having simple lateral ties with two legged stirrups and
diamond stirrups. From the results it concludes that Total
Deformation for two legged stirrups in NSC is greater than
diamond NSC by 47.24%. Total Deformation for two legged
stirrups in HSC is greater than diamond HSC by 47.72%. Total
Deformation for two legged stirrups in SFRC is greater than
diamond SFRC by 5.47%.
Graph 1: Total Deformation
37. Above graph shows the result for Normal Stress for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Normal Stress for
diamond NSC is greater than two legged stirrups in NSC by
17.91%. Normal Stress for two legged stirrups in HSC is greater
than diamond HSC by 0.43%. Normal Stress for two legged
stirrups in SFRC is greater than diamond SFRC by 18.64%.
Graph 2: Normal Stress (mm)
39. Above graph shows the result for Strain Energy in mm for
columns having simple lateral ties with two legged stirrups and
diamond stirrups. From the results it concludes that Strain Energy
for two legged stirrups in NSC is greater than diamond NSC by
16.45%. Strain Energy for two legged stirrups in HSC is greater
than diamond HSC by 16.47%. Strain Energy for diamond SFRC
is greater than two legged stirrups in SFRC by 52.6%.
Graph 3: Strain Energy (Mpa)
41. Above graph shows the result for Maximum Principal Stress for
columns having simple lateral ties with two legged stirrups and
diamond stirrups. From the results it concludes that Maximum
Principal Stress for two legged stirrups in NSC is greater than
diamond NSC by 0.42%. Maximum Principal Stress for two
legged stirrups in HSC is greater than diamond HSC by 0.48%.
Maximum Principal Stress for two legged stirrups in SFRC is
greater than diamond SFRC by 0.59%.
Graph 4: Maximum Principal Stress
43. Above graph shows the result for Shear Stress for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Shear Stress for two
legged stirrups in NSC is greater than diamond NSC by 35.07%.
Shear Stress for two legged stirrups in HSC is greater than
diamond HSC by 35.16%. Shear Stress for two legged stirrups in
SFRC is greater than diamond SFRC by 35.96%.
Graph 2: Shear Stress
45. Above graph shows the result for Equivalent Stress for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Equivalent Stress for
diamond NSC is greater than two legged stirrups in NSC by
0.31%. Equivalent Stress for diamond HSC is greater than two
legged stirrups in HSC by 0.39%. Equivalent Stress for diamond
SFRC is greater than two legged stirrups in SFRC by 5.17%.
Graph 3: Equivalent Stress
47. Above graph shows the result for Total Heat Flux for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Total Heat Flux for
diamond NSC is greater than two legged stirrups in NSC by
17.74%. Total Heat Flux for diamond HSC is greater than two
legged stirrups in HSC by 18.57%. Total Heat Flux for diamond
SFRC is greater than two legged stirrups in SFRC by 17.94%.
Graph 4: Total Heat Flux
48. CONCLUSION
The results are taken for Total Heat Flux for columns
having simple lateral ties with two legged stirrups and
diamond stirrups. From the results it concludes that Total
Heat Flux for diamond NSC is greater than two legged
stirrups in NSC by 17.74%. Total Heat Flux for diamond
HSC is greater than two legged stirrups in HSC by
18.57%. Total Heat Flux for diamond SFRC is greater
than two legged stirrups in SFRC by 17.94%.
49. The results are taken for Equivalent Stress for columns
having simple lateral ties with two legged stirrups and
diamond stirrups. From the results it concludes that
Equivalent Stress for diamond NSC is greater than two
legged stirrups in NSC by 0.31%. Equivalent Stress for
diamond HSC is greater than two legged stirrups in HSC
by 0.39%. Equivalent Stress for diamond SFRC is greater
than two legged stirrups in SFRC by 5.17%.
50. The results are taken for Shear Stress for columns having simple
lateral ties with two legged stirrups and diamond stirrups. From
the results it concludes that Shear Stress for two legged stirrups
in NSC is greater than diamond NSC by 35.07%. Shear Stress for
two legged stirrups in HSC is greater than diamond HSC by
35.16%. Shear Stress for two legged stirrups in SFRC is greater
than diamond SFRC by 35.96%.
The results are taken for Maximum Principal Stress for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Maximum Principal
Stress for two legged stirrups in NSC is greater than diamond
NSC by 0.42%. Maximum Principal Stress for two legged
stirrups in HSC is greater than diamond HSC by 0.48%.
Maximum Principal Stress for two legged stirrups in SFRC is
greater than diamond SFRC by 0.59%.
51. The results are taken for Strain Energy in mm for columns having
simple lateral ties with two legged stirrups and diamond stirrups.
From the results it concludes that Strain Energy for two legged
stirrups in NSC is greater than diamond NSC by 16.45%. Strain
Energy for two legged stirrups in HSC is greater than diamond
HSC by 16.47%. Strain Energy for diamond SFRC is greater than
two legged stirrups in SFRC by 52.6%.
The results are taken for Normal Stress for columns having
simple lateral ties with two legged stirrups and diamond stirrups.
From the results it concludes that Normal Stress for diamond
NSC is greater than two legged stirrups in NSC by 17.91%.
Normal Stress for two legged stirrups in HSC is greater than
diamond HSC by 0.43%. Normal Stress for two legged stirrups in
SFRC is greater than diamond SFRC by 18.64%.
52. The results are taken for Total Deformation in mm for columns
having simple lateral ties with two legged stirrups and diamond
stirrups. From the results it concludes that Total Deformation for
two legged stirrups in NSC is greater than diamond NSC by
47.24%. Total Deformation for two legged stirrups in HSC is
greater than diamond HSC by 47.72%. Total Deformation for two
legged stirrups in SFRC is greater than diamond SFRC by 5.47%.
53. FUTURE SCOPE
Further studies can be undertaken for configurations of
lateral reinforcement other than diamond shape done here.
Other column shapes can also be considered for future
study.
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