The document provides an introduction to the repair and rehabilitation of structures. It discusses factors contributing to damages in buildings from construction through use. Common causes of distress in concrete structures are then outlined, including construction errors, environmental factors, and chemical reactions. The objectives of conducting a condition survey of a distressed structure are presented, including identifying causes and assessing the extent of damage. The stages of a condition survey are described, beginning with a preliminary inspection, planning, visual inspection, and potentially field and laboratory testing. Classification of damage into different classes is also covered to help assess repair needs.
Techniques for various structural repairUdayram Patil
Structural damage is crucial to safety. Proper remedial measures should always taken to avoid measure loss. This presentation provided various measure to repair structural damage.
This power point presentation gives you information about the various chemicals, admixtures used to repair members and improve the properties of concrete. it gives you information about the various types of concrete. it gives you information about the various methods of repair.
This presentation has been prepared by civil engineering students of Tolani Foundation Gandhidham Polytechnic:
DHAWANI LAVISH
GAYAKWAD TEJAS
GORASIYA MAYUR
HIRANI YATIN
KATARMAL DARSHAN
LALWANI PIYUSH
MALI VISHNU
PATEL PARTH
PRAJAPATI JAYESH
PRAJAPATI KALPESH
Thank You!!
Techniques for various structural repairUdayram Patil
Structural damage is crucial to safety. Proper remedial measures should always taken to avoid measure loss. This presentation provided various measure to repair structural damage.
This power point presentation gives you information about the various chemicals, admixtures used to repair members and improve the properties of concrete. it gives you information about the various types of concrete. it gives you information about the various methods of repair.
This presentation has been prepared by civil engineering students of Tolani Foundation Gandhidham Polytechnic:
DHAWANI LAVISH
GAYAKWAD TEJAS
GORASIYA MAYUR
HIRANI YATIN
KATARMAL DARSHAN
LALWANI PIYUSH
MALI VISHNU
PATEL PARTH
PRAJAPATI JAYESH
PRAJAPATI KALPESH
Thank You!!
Introduction about Repair & Rehabilitation of Structures
Repair of Structures
Rehabilitation of Structures
Maintenance of Structures
Various Methods of Maintenance
this presentation deals with the different types of cracks generated in concrete during its usage and after its application and also methods to retrofit these cracks
The vacuum dewatering process basically improves strength, durability, and other properties of concrete by reducing the water-cement ratio immediately after the mix is placed, usually in floors and other flatwork. A Bridgeport, Connecticut vacuum dewatering demonstration, although it involved no new ...
vacuum dewatering system
vacuum dewatering pump
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wellpoint pump systems
dewatering pump system
dewatering pump
dewatering wellpoint
small wellpoint dewatering systems
interesting civil engineering topics
civil engineering topics for presentation
civil seminar topics ppt
civil engineering seminar topics 2018
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Retrofitting is the seismic strengthening of existing damaged or undamaged structures.
Retrofitting a building involves changing its systems or structure after its initial construction and occupation. This work can improve amenities for the building's occupants and improve the performance of the building
Design & Construction Errors- How it Affects Repair and Rehabilitation of Str...Srishti Wakhloo
The ultimate guide to design and construction errors and how it affects the repair and rehabilitation of structures. This data has been compiled after visiting several websites and reading books. It is mainly for the purpose of civil engineering students for the subject "Building Maintenance and Repairs".
Introduction about Repair & Rehabilitation of Structures
Repair of Structures
Rehabilitation of Structures
Maintenance of Structures
Various Methods of Maintenance
this presentation deals with the different types of cracks generated in concrete during its usage and after its application and also methods to retrofit these cracks
The vacuum dewatering process basically improves strength, durability, and other properties of concrete by reducing the water-cement ratio immediately after the mix is placed, usually in floors and other flatwork. A Bridgeport, Connecticut vacuum dewatering demonstration, although it involved no new ...
vacuum dewatering system
vacuum dewatering pump
vacuum dewatering box
wellpoint pump systems
dewatering pump system
dewatering pump
dewatering wellpoint
small wellpoint dewatering systems
interesting civil engineering topics
civil engineering topics for presentation
civil seminar topics ppt
civil engineering seminar topics 2018
best seminar topics for civil engineering
seminar topics pdf
seminar topics for mechanical engineers
seminar topic for civil engineering pdf
Retrofitting is the seismic strengthening of existing damaged or undamaged structures.
Retrofitting a building involves changing its systems or structure after its initial construction and occupation. This work can improve amenities for the building's occupants and improve the performance of the building
Design & Construction Errors- How it Affects Repair and Rehabilitation of Str...Srishti Wakhloo
The ultimate guide to design and construction errors and how it affects the repair and rehabilitation of structures. This data has been compiled after visiting several websites and reading books. It is mainly for the purpose of civil engineering students for the subject "Building Maintenance and Repairs".
Repair and Rehabilitation of Historical StructuresAravind Samala
Repair, Retrofitting and Rehabilitation of Heritage buildings and historical structures. As Heritage buildings serves the integrity in and around the world, there is a great need to repair and restore them.
STRUCTURAL CRACKS: 1. Epoxy injection 2. Polyurethane injection 3. Stitching of cracks Problem Identification Selection of suitable solution
9. EPOXY INJECTION 60002C Epoxy Injection Pump Epoxy grout consists of epoxy resin, epoxy hardener and sand/aggregates. Epoxy grout is non-porous and wouldn’t absorb any contaminant or stains.
10. STRUCTURAL CRACKS: 1. Epoxy injection 3. Stitching of cracks Problem Identification Selection of suitable solution 2. Polyurethane Injection
11. POLYURETHANE INJECTION Installed Injection Packer Polyurethane Crack Injection Polyurethane injection involves a high pressure (typically 1500-3200 psi) injection of activated polyurethane through injection packers hammered into drilled holes. These fast-setting foams are effective alternatives for applications involving only crack sealing (waterproofing) and not structural repair.
12. STRUCTURAL CRACKS: 1. Epoxy injection 2. Polyurethane Injection Problem Identification Selection of suitable solution 3. Stitching of cracks
13. STITCHING OF CRACKS
14. ROOF LEAKAGES 1. Replacement of damaged roof with new clay roof tile and rearrangement of sealant. 2. Replacement of damaged roof portion by Asbestos roof and refill of sealant 3. Lead flashing Problem Identification Selection of suitable solution
15. Peeling of walls and ceiling The most suited and effective solution for peeling of walls or plaster is Mughal Plastering i.e. Plastering with lime mortar. Its lifetime is 10 years. Mold stains The effective solution is applying soap water under high pressure using pressure nozzle, controller and tube. Vegetation growth The materials used to remove vegetation growth are Glyphosate, ammonia solution and lime mortar. Maluti temples, Dumka District, Jharkhand Problem Identification Selection of suitable solution
Distress of concrete structure & their repair techniques seminarMarcep Inc.
DAMAGES & FAILURES OF STRUCTURE
LOADS ON STRUCTURES
CAUSES OF FAILURE
FOUNDATION DAMAGE
INSPECTION
QUICK ASSESSMENT & CASE STUDIES
Case histories of failures and damages under various
agencies
Methods for solving Damage equations to predict
failures of Structures
Investigation of Damages & failures, birth & growth of
cracks
Analytical Studies for damage verification & for failure
mechanism
How Structural deterioration reliability used to calculate
probabilities of Strucutural failure
Dead loads, Live loads, water pressure, Earth pressure,
etc
The varying deterrent effect of all loads on Structures
Load & Resistance factor Design (LRFD)
Over loading, subsidence, chemical attack, dynamic
load, etc.
Poor training of field inspectors
Lack of appropriate professional design & construction
experience
Unwarranted belief in specified extreme loads and
properties
Substandard quality of construction materials
Inadequate supervision in constructing building
structures
Poor workmanship, lack of soil analysis
Settlement, Water logging, vegetation , etc
Damage from earthquakes and other natural causes.
Foundation failures and cracks
Distinguish, Identify & Assessment Pre-existing
foundation Damage
Visual, Measurement, NDT etc
Reliability Analysis & Periodic Inspection of Structures
Collective Inspection of Regular Structures
Risk based inspection (RBI) planning
RETROFITTING
SETTLEMENT REPAIRS
CRACK REPAIRS
CONCRETE REPAIRS
CFRP, GFRP, NSM
JACKETING REPAIRS
QUICK ASSESSMENT & CASE STUDIES
Methods, wrapping with FRP, jacketing, etc
Performance based optimal seismic retrofitting
Time-Dependent Behavior of FRP Retrofitting
Underpinning
Repair techniques for Settled Foundations
Repair Methods for Settled foundations
Materials, injection Method, stitching, etc
Inspection , Control & Repair of Cracks
Surface preparation
Identification, Assesment of the cause & extent of
the problem
Safety measures to avoid crack repair
Effectiveness of Concrete Repair
Application Method of Concrete Repair
Conventional repair of reinforced Concrete
Beam, Column etc
Strengthening & rehabilitation by reinforced
concrete jacketing Repairs
Predicting the Shear Capacity of Reinforced Concrete Slabs subjected to Conce...Eva Lantsoght
The shear problem is typically studied by testing small, heavily reinforced, slender beams subjected to concentrated loads, resulting in a beam shear failure, or by testing slab-column connections, resulting in a punching shear failure. Slabs subjected to concentrated loads close to supports, as occurring when truck loads are placed on slab bridges, are much less studied. For this purpose, the Bond Model for concentric punching shear was studied at first. Then, modifications were made, resulting in the Modified Bond Model. The Modified Bond Model takes into account the enhanced capacity resulting from the direct strut that forms between the load and the support. Moreover, the Modified Bond Model is able to deal with moment changes between the support and the span, as occurs near continuous supports, and can take into account the reduction in capacity when the load is placed near to the edge. The resulting Modified Bond Model is compared to the results of experiments that were carried out at the Stevin laboratory. As compared to the Eurocodes (NEN-EN 1992-1-1:2005) and the ACI code (ACI 318-11), the Modified Bond Model leads to a better prediction.
The construction activity in India has been increasing geometrically without matching
increase in the availability of quality inputs, in terms of materials and skilled workmen. The gap
between the quality planned and the quality achieved continues to widen. The factors contributing to
damages/distress due to various causes including leakage/seepage have, thus, become intrinsic right
from the construction stage.
This topic discusses in general about the repair, maintenance and their strategies to be followed. It is also discussed about the assessment procedures and investigations to be done while repairing any structures.
REHABILITATION/RETROFITING OF CONCRETE STRUCTURES ALONG WITH CASE STUDYcivej
The construction material mainly concrete is being used extensively for various types of construction
projects. However, the deterioration of Reinforced Concrete structures is recognized as a major problem
worldwide. Apart from requiring regular maintenance, many structures require extensive
Repair/Rehabilitation/Retrofitting. Over a period of time, as these structures become older, we find in them
certain degradation or deterioration with resultant distress manifested in the form of cracking, splitting,
delaminating, corrosion etc. Such deteriorated structures can be rehabilitated and retrofitted by using
various types of admixtures & modern repair materials. The paper brings out the present state of concrete
structures & the major areas where improvement is needed during its service life stage for sustainable
development & also the method of carrying out Repair/Rehabilitation/Retrofitting.This has been brought in
details in the paper along with Case study, where the Author of the paper was directly involved in planning
and execution of job.
Methodology for Prevention and Repair of Cracks in BuildingGRD Journals
Cracks in building are a common occurrence. It affects the stability and appearance of buildings. So, it is important to understand the cause of cracks and the effective measures should be taken for prevention. Though cracks in concrete cannot be prevented entirely but they can be prevented by using proper material and technique of construction and considering criteria. Sometimes water penetrates through cracks in building and cause severe damage to building. There are many reason of occurrence of cracks like moisture, thermal movement, elastic deformation, chemical reaction, foundation movement, vegetation and earthquake. We all dream of a house structurally safe and aesthetically beautiful but it is not so easy. So, timely identification of such cracks and adopting preventive measures is essential. In this paper, we will discuss about the methodology for prevention and repair of cracks in building. This research paper also gives information about result of Rebound Hammer Test and Ultrasonic Pulse Velocity Test for determining strength of concrete. Because strength of concrete is also an influencing factor for repairing cracks in building. So, we can say if crack repair is assumed to be building of structure then this paper can be assumed as foundation of it.
Citation: Dimpy B. Patel, Bhagwan Mahavir College Of Engineering And Technology; Shyam Doshi ,Bhagwan Mahavir College Of Engineering And Technology; Kevina B. Patel ,Bhagwan Mahavir College Of Engineering And Technology; Kajal B. Patel ,Bhagwan Mahavir College Of Engineering And Technology; Pinal D. Mavani ,Bhagwan Mahavir College Of Engineering And Technology. "Methodology for Prevention and Repair of Cracks in Building." Global Research and Development Journal For Engineering 33 2018: 52 - 58.
Structural Analysis for Rehabilitation of Reinforced Concrete StructureIJERA Editor
The structural element – basement raft of the Beach resort started showing symptoms of distressed within10
years on its completion. This deterioration has aggravated further during next 3-4 years and the basement floor
became obsolete functionally. Therefore, it was decided to identify the cause of failure of the structural element
in terms of inadequacy of the structural element. The failure may be due to inadequacies in the design and
detailing or defects during construction. This study dealt with the analysis of existing structural member for its
design adequacy and to ascertain defects during construction. Design adequacy was ascertained using computer
aided software- (STADD -Pro). Defects during construction have been ascertained by establishing the Sectional
details of the As built basement raft in terms of dimensional parameters, noted on site as well as quality
parameters confirmed in laboratory testing. On analysing these cases, the actual cause of the structural failure of
the basement raft has been concluded.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
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.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
2. Since 1950s, the construction activity in India has been
increasing geometrically without matching increase in the
availability of quality inputs, in terms of materials and skilled
workmen. The gap between the quality planned and the quality
achieved continues to become wider. The factors contributing
to damages/distresses in buildings have, thus, become intrinsic
right from the construction stage. Construction documents
contain adequate specifications and instructions required to
execute quality works. However, they remain as written
document without achieving the desired level of results,
because of lack of understanding of their significance by the
field engineers. Standard cube test results are taken as a
measure of quality in the construction.
BITS Edu Campus
Prof. Ankit Patel
2
3. Whereas the factors such as method of placing, compaction and
curing of concrete, which have significant influence on the
quality achieved in the hardened concrete, are given scant
attention. Many a times, the quality of concrete as placed and
hardened in position has no correlation to the cube test results,
which are used for quality control measures. Procedures,
mandatory or otherwise, for periodic inspection of buildings
and documenting defects in logical manner, and recording of
structural repairs already carried out, are generally not followed
or maintained.
The word ‘repair’ normally conveys small and ordinary repairs,
which are not of structural significance. But the aim of
rehabilitation is to restore a distressed structure back to its
original durability.
BITS Edu Campus
Prof. Ankit Patel
3
4. Repair, Rehabilitation and Maintenance
• Repair: Repair is the process of restoring something is
damaged or deteriorated or broken, to good condition.
• Rehabilitation: Rehabilitation is the process of returning a
building or an area to its previous good conditions.
• Maintenance: Maintenance is the act of keeping something in
good condition by checking or repairing it regularly.
BITS Edu Campus
Prof. Ankit Patel
4
6. Distress In Structures:
Distress in Structure: Damage in Structure
Concrete may suffer distress or damage during its life period due
to number of reasons. Because of varying conditions under which
it is produced at various locations, the quality of concrete suffers
occasionally either during production or during service conditions
resulting in distress.
BITS Edu Campus
Prof. Ankit Patel
6
7. Causes of Distress(Damage) in Concrete
• Structural causes ie (Externally applied loads, Environmental
loads, Accidents)
• Construction Errors & Design Errors
• Poor Construction Practices
• Construction Overloads
• Drying Shrinkage
• Thermal Stress
• Chemical Reactions
• Weathering
• Corrosion
• Acid attack
BITS Edu Campus
Prof. Ankit Patel
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8. Causes of Distress(Damage) in Concrete
For Plastic Concrete Distress:
Plastic Shrinkage
Early Removal Formwork
Improper design of formwork
BITS Edu Campus
Prof. Ankit Patel
8
11. Causes of Distress(Damage) in Concrete
Voids in concrete
Rust Stain
Drying Shrinkage
Plastic Shrinkage
scaling
BITS Edu Campus
Prof. Ankit Patel
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12. Blow holes in concrete
Blow holes are individual, generally rounded, cavities on vertical surfaces of
concrete, generally less than 10 mm across. They are caused by air in the
concrete being trapped against the form face, sometimes due to insufficient
vibration. Some blow holes are almost inevitable unless a permeable formwork
material is used. The occurrence of blow holes can be minimized by the use of a
suitable release agent on the surface of the formwork and the use of adequate
vibration. In addition the concrete should have adequate workability. Blow holes
are a cosmetic problem only and will not affect the long-term performance of the
concrete structure
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Prof. Ankit Patel
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13. Plucked Surface in concrete
• This appears as surface material lost upon striking the formwork
• Normally occurs when the concrete surface is not of sufficient strength when
striking the formwork. Could be due to cold weather, retarded surface, high
cement replacement or a combination thereof.
• Allowing the concrete to gain sufficient strength reduces the risk of its
occurrence and is generally accepted as being 5MPa.
BITS Edu Campus
Prof. Ankit Patel
13
15. Construction Errors and Design Deficiencies:
Poor construction practices and negligence can cause defects that lead to the
cracking and concrete deterioration. These include:
Scaling, Dusting of concrete
Improper alignment of formwork
Movement of formwork
Improper location of reinforcing steel
Improper curing
Errors made during construction such as adding improper amounts of water to
the concrete mix, improper curing cause distress and deterioration of the
concrete. Proper mix design , placement and curing of the concrete, as well as
an experienced contractor are essential to prevent constructing errors from
occurring. Construction errors can lead to some of the problem such as scaling
and cracking. Honeycombing and bug holes can be observed after
construction. Honeycombing can be recognized by expose coarse aggregate on
the surface without any mortar covering or surrounding the aggregate particles.
The honeycombing may extend deep into the concrete. Honeycombing can be
caused by a poorly graded concrete mix, by too large of aggregates, or
insufficient vibration at the time of placement .
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Prof. Ankit Patel
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16. Construction Errors and Design Deficiencies:
Bug holes is the term used to describe small holes that are noticeable on the
surface of the concrete. Bug holes are generally caused by too much sand in a
mix, a mix that is too lean or excessive amplitude of vibration during placement.
Bug holes may cause durability problems with the concrete should be monitors.
Design Errors:
It is broadly divided into two parts
1. Inadequate structural design:
The failure mechanism is due to over stressing of concrete beyond its capacity.
These defects will me manifested in the concrete either by cracking or spalling. If
the concrete experience high compressive stresses then spalling will occur. If
concrete expose to high torsional or shearing stresses then spalling or cracking
may occur and high tensile stresses will cause the concrete to crack. Such defects
will be present in the areas where high stresses are expected. Through visual
inspection engineer should decide weather to proceed for detail analysis. These
problems can be prevented with a careful review of design calculations and
detailing.
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Prof. Ankit Patel
16
17. Construction Errors and Design Deficiencies:
2. Poor Design Detail:
An adequate design does not guarantee a satisfactory function without
including design detailing. Detailing is an important component of
structural design. Poor detailing may or may not directly lead to a
structural failure but it may contribute to the deterioration of the concrete.
In order to fix a detailing defect it is necessary to correct the detailing and
not to respond to the symptoms only. Some of the design and detailing
defects include:
1. Abrupt Changes in the section
2. Insufficient reinforcement at corners and openings
3. Inadequate provision of drainage
4. Inadequate expansion joint
5. Material incompatibility
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Prof. Ankit Patel
17
18. Condition Survey
Condition Survey is an examination of concrete for the purpose of
identifying and defining area of distress. While it is referred in
connection with survey of concrete and embedded reinforcement that is
showing some degree of distress, its application is recommended for all
buildings and structures. The system is designed to be used for recording
the history of the project from its inception to completion and
subsequent life.
BITS Edu Campus
Prof. Ankit Patel
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19. Objectives of Condition Survey
• The objective of Condition Survey of a building structure is
• To identify Causes of distress and Their sources;
• To assess The extent of distress occurred due to corrosion, fire,
earthquake or anyother reason, The residual strength of the structure
and Its rehabilitability;
• To prioritise the distressed elements according to seriousness for
repairs and
• To select and plan the effective remedy.
• “Find the cause, the remedy will suggest itself”. Sometimes, the
source of the cause of distress is different than what is apparently
seen. It is, therefore, essential that the engineers conducting condition
survey determine the source(s) of cause so as to effectively deal with
it and minimize their effects by proper treatment.
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Prof. Ankit Patel
19
20. Stages of Condition Survey
Stages for carrying out Condition Survey largely depend on field
conditions, user habits, maintenance, etc. Condition Survey of a
building/structure is generally undertaken in four different stages to
identify the actual problem so as to ensure that a fruitful outcome is
achieved with minimum efforts & at the least cost. The four stages of
Condition Survey described are:
Preliminary Inspection,
Planning,
Visual Inspection,
Field and Laboratory testing
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Prof. Ankit Patel
20
21. 1. Preliminary Inspection
A.The primary objective of the preliminary inspection is:
1. To assess and collect following necessary information for a thoughtful
planning before a condition survey is physically undertaken:
Background history of the distressed structure From the
Owners/Clients From the occupants of building, general public, etc
based on personal enquiries;
Notes and records of earlier repairs, if carried out,
All possible relevant data and information;
The safety requirements for condition survey team;
Necessary site preparations including access scaffolds, working
platforms, etc, if any;
The approx. time required for survey;BITS Edu Campus
Prof. Ankit Patel
21
22. 1. Preliminary Inspection
The extent and quantum of survey work;
The requirement of field-testing equipment's, Tools for sampling.
2. To advise the client/owner of the building in regard to take immediate
safety measures.
3. To define the scope of work of field investigations with the
Clients/Owners.
B. Basic Information Gathering: A programme has to be evolved to
obtain as much information as possible about the distressed structure at
reasonable cost and in a reasonable time. Accordingly, the information
required from the owner/client has to be listed out. Even though; many
construction details and other related information may not be available
with the owners/clients, yet as much as information and details as
possible be gathered during the Preliminary Site Visit. Before
undertaking a Condition Survey of a building/structure, the following
essential information is required and be obtained from the clients/owners:
BITS Edu Campus
Prof. Ankit Patel
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23. 1. Preliminary Inspection
Period of construction;
Construction details including architectural, structural and as built
drawings;
Exposure conditions of structure;
Present use of structure;
Previous changes in use, if any;
Record of structural changes made, if any;
Record of first occurrence of deterioration, if any;
Details of repairs, if carried out in the past;
Reports of previous investigations/condition surveys, if any;
Photographs of distressed portions of structure.BITS Edu Campus
Prof. Ankit Patel
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27. 1. Preliminary Inspection
C. Photographic Record: It is always necessary to carry a camera with
flash during such ‘Preliminary inspection’ and take necessary photographs
of the distressed structure and its members. Preliminary Inspection and
collection of data would be helpful in planning, the Condition Survey for
field investigations. This allows a reasonably sufficient understanding of
the cause of distress for an experienced Rehabilitation Engineer.
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28. General approach for pre-repair
evaluation of distress concrete
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29. 2. Planning Stage
Planning stage involves preparation of field documents, grouping of
structural members and classification of damage as under:
• Preparation of Field Documents:
• For condition survey, the following are required to be prepared:
Survey objective;
Scope of work;
Method of survey;
The field and laboratory testing requirements and field
equipment's & tools required for the same;
Maintenance and repair records.
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30. 2. Planning Stage
Required number of photo copy of available drawings;
Floor plans based on field measurements;
Work sheets and tables for recording in a logical manner all
information, test results including field data gathered;
Previous Condition Survey results and Investigation Reports, if
any;
Maintenance and repair records.
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31. 2. Planning Stage
Grouping of the Structural members:
Soon after the preliminary site visit and on obtaining of building plans,
the structural members shall be grouped as per their type and based on
similarity of exposure conditions for proper appreciation of the cause of
distress. For example in a building subjected to normal environmental
attack, the grouping could be done as under:
External columns/beams would be subjected to more severe
environmental attack than the internal structural members of a
building and could be grouped in two broad groups.
Even from amongst the external columns, those at corners or projected
out are likely to be exposed more due to adjacent faces being exposed
than those not at corners or un-projected columns. Hence to be
grouped separately.BITS Edu Campus
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32. 2. Planning Stage
The members subjected to dampness/wetting/drying located in or
around the toilet shafts are likely to undergo similar class of distress
and be grouped separately.
Structural members with different protective finishes have to be
grouped separately.
• Classification of Damage:
• Based on the preliminary data collected and site visit, the
rehabilitation engineer should interpret rules and subdivide the repair
classification broadly in to five classes as ‘Class 0’ to ‘Class 4’ named
as Cosmetic Repair, Superficial Repair, Patch, Repair, Principal
Repair and Major Repair.
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35. 3. Visual Inspection
1. Visual Inspection and observations:
Visual examination of a structure is the most effective qualitative
method of evaluation of structural soundness and identifying the
typical distress symptoms together with the associated problems.
This provides valuable information to an experienced engineer in
regard to its workmanship, structural serviceability and material
deterioration mechanism.
It is meant to give a quick scan of the structure to assess its state
of general health.
The record of visual inspection is an essential requirement for
preparation of realistic bill of quantities of various repair items.
Experienced engineers should carry out this work as these forms
the basis for detailing out the plan of action to complete the
diagnosis of problems and to quantify the extent of distress.BITS Edu Campus
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36. 3. Visual Inspection
Simple tools and Instruments like camera with flash, magnifying
glass, binoculars, and gauge for crack width measurement, chisel
and hammer are usually needed. Occasionally, a light
platform/scaffold tower can be used for access to advantage.
The study of crack pattern leads to the primary cause of damage.
The mesh pattern generally suggests that the distress in a structure
could be due to drying shrinkage, frost action or alkali aggregate
reaction.
The cracking along the reinforcement indicates that the damage
could be due to corrosion of reinforcement.
The study of colour and texture of the concrete and condition of
fixtures is very much useful in investigation of fire damage
structure.
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37. 3. Visual Inspection
2. Questioning of personnel/Scrutiny of field data and records:
The questioning of personnel and the scrutiny of field data and records is
carried out for the following:
Grade of concrete adopted
Cube test results
Type of materials and sources
Construction details
Environmental conditions
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38. 3. Visual Inspection
Commonly
Observed Order
Location of RCC component
Deterioration of RCC Building
First Wet / water stagnating areas with RCC elements located on external
direct exposed walls/slabs and frequented with alternate wetting/drying
cycle.
Second Thin exposed non structural RCC elements e.g. chhajjas, railings etc.
Third Terrace RCC slab with ineffective insulation, water proofing and
drainage systems
Fourth Wet areas with RCC elements located on inner unexposed walls and
frequented with alternate wetting/drying cycle
Fifth Beams/columns with one face exposed direct to sun and rain and the
other face unexposed.
Sixth Beams/Columns exposed to rain and sun from all sides.
Last Beams/Columns/Slabs located in the interior of building.
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39. 3. Visual Inspection
Types of cracks in concrete structures:
Structural cracks.
Non Structural Cracks.
Structural Cracks
• Structural cracks are those which result from incorrect design, faulty
construction or overloading and these may endanger the safety of a
building and their inmates.
Non Structural Cracks.
• Non Structural cracks occur mostly due to internally induced stresses
in building materials. These cracks normally do not endanger the
safety but may look unsightly, create an impression of faulty work or
give a feeling of instability.
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40. 3. Visual Inspection
Defects in Concrete:
• Concrete defects can be broadly classified into two categories :
• 1. Macro Defects:
• If these defects are present, concrete has low strength and will rapidly
deteriorate due to easy ingress of water and other chemicals.
Invariably, structure will require repairs within a few years of its
construction. Causes will have to be analysed and defects removed
before doing any additional protective treatment. Often,
waterproofing of concrete slabs is carried out superficially and it fails
to give the desired benefit because the defective concrete below this
waterproofing layer has not been treated to seal the macro/micro
defects which existed within the concrete slab. The main causes of
these defects are generally due to inadequacies in design and / or
construction practices.BITS Edu Campus
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41. 3. Visual Inspection
• 2 Micro Defects:
• These defects are not visible to the naked eye. They are usually very
fine voids caused by large capillary pores resulting from the use of
low grades (strength) of concrete with high water to cement ratio.
• They could also occur due to addition of excess water or high water
to cement ratio of concrete mix. Fine cracks are generally present in
concrete and can occur due to various reasons. They do not pose a
serious threat to concrete deterioration initially as they are generally
not deep and are discontinuous. With lapse of time due to variations
in temperatures, changes in weather conditions, changes in loading
conditions they increase in depth, length and width and combine with
other fine cracks to create continuous passage for moisture, chlorides,
sulphates and other chemicals from the environment to enter and start
corrosion of steel in concrete and other deleterious reactions.BITS Edu Campus
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42. 3. Visual Inspection
To conclude, macro defects and micro defects in concrete are both
harmful to the health of buildings and can cause deterioration of
concrete depending on the extent of their presence, environmental
conditions around the building and maintenance done during its life
cycle. However macro defects by virtue of being larger can cause faster
deterioration and more damage to the structure than the micro defects
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43. 3. Visual Inspection
Obstructions to visual inspection:
Recently done paints, patch work of replaster, false ceiling etc. are
likely to create obstructions to visual inspection. Carefully analyze
such areas
Insufficient light inside the building.
The access height from within and from outside during visual
inspection could also be a major problem.
Types of cracks and their pattern:
It is generally easy to differentiate various types of cracks and relate
them with the cause of distress. The location of cracks and their
pattern give the first indication of the problem.
Cracking and spalling, or rust staning are visual indication of the
corrosion of steel in concrete. Corrosion cracks run along the
reinforcement location.
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44. 3. Visual Inspection
A mesh pattern of cracks suggests drying shrinkage, alkali aggregate
reaction or frost attack,
Cracks at right angle to main reinforcement are generally associated
with structural deficiency.
Cracking along the bar can be an important indication that the
reinforcements are subjected to corrosion.
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46. 3. Visual Inspection
Worksheet
The visual inspection shall largely cover:
• Recording of Areas of high distress;
• Cracks & their location;
• Excessive deflection;
• Exposure conditions of various distressed areas;
• Moisture, leakage/ seepage & dampness locations;
• Abnormal vibrations in structure, if any;
• Algae, fungus growth and/or efflorescence etc and their locations;
• Photographic records,
Visual inspection is, therefore, the best way of qualitative assessment of
any structure. BITS Edu Campus
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47. 4. Field/laboratory Testing Stage
• Objective:
It may neither be feasible nor is the practice to conduct field/laboratory
testing on every structural member in an existing distressed building.
The field/laboratory testing of structural concrete and reinforcement is to
be undertaken, basically for validating the findings of visual inspection.
These may be undertaken on selective basis on representative structural
members from each of the various groups based on exposure conditions
as explained in the preceding sections.
The programme of such testing has to be chalked out based on the record
of visual inspection.
After identification of weak zones in a structure, detailed assessment of
insitu quality of material is done. A number of test have been developed
for different properties of concrete.
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48. Considerations for Repair Strategy
In the Condition Survey Report, before arriving at the Repair Strategy, it
shall include the following considerations:
Identification of the cause of problem and its source is the fundamental
to the success or failure of the repair. A lack of attention at this point can
put at risk the whole job.
For arriving at an effective and economical solution, systematic
documentation of all observations is essential.
Available space and accessibility will determine the selection of repair
method and repair strategy.
Depending upon the scope and scale of repairs, the repair strategy has to
suit the on-going activities in the building.
The prioritization of repairs and their sequencing are important
components for deciding the repair strategy.
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49. Considerations for Repair Strategy
Major repair procedure may demand propping the structural members to
relieve a part or full component of the load acting on the member. If the
building requires extensive propping, vacating the building may become
the pre-requisite.
Safety measures to prevent any immediate major mishap shall be
prescribed without loosing further time.
The report should also include requirements on safety measures to be
adopted during execution of repair jobs.
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50. NON DESTRUCTIVE EVALUATION
TESTSA number of non-destructive evaluation (NDE) tests for concrete
members are available to determine in-situ strength and quality of
concrete. Some of these tests are very useful in assessment of damage to
RCC structures subjected to corrosion, chemical attack, and fire and due
to other reasons. The term ‘non destructive’ is used to indicate that it
does not impair the intended performance of the structural member
being tested/investigated. The non-destructive evaluation has been
broadly classified under two broad categories via ‘in-situ field test’ and
‘laboratory test’. These tests have been put under four categories
depending on the purpose of test as under:
In-situ Concrete Strength
Chemical Attack
Corrosion Activity
Fire DamageBITS Edu Campus
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51. Concrete Strength Assessment
A. Objective:
Generally, in-situ non-destructive evaluation of concrete is to have an
overall idea of the quality of concrete.
In some cases, a sufficiently accurate estimate of quantitative value of
concrete strength is required for assessment of load carrying capacity of
a structural member. The need for such an estimate may arise during
evaluation of change in usage of structure, modification or extension of
the original structure or damage due to fire, earthquake, etc
B. Limitations:
The accuracy is not very high as most of the non-destructive methods of
evaluation of concrete strength are based on indirect measurement of
concrete strength.
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52. Rebound Hammer Test
The operation of Rebound Hammer (also called Schmidt’s Hammer)
is illustrated in Figure When the plunger of rebound hammer is
pressed against the surface of concrete, a spring controlled mass with
a constant energy is made to hit concrete surface to rebound back.
This test is conducted to assess the relative strength of concrete based
on the hardness at or near its exposed surface and to identify relative
surface weaknesses in cover concrete and also can be used to
determine the relative compressive strength of concrete. Locations
possessing very low rebound numbers will be identified as weak
surface concrete and such locations will be identified for further
investigations like corrosion distress, fire damage and/or any other
reason including original construction defects of concrete. The extent
of rebound, which is a measure of surface hardness, is measured on a
graduated scale. This measured value is designated as Rebound
Number (a rebound index). A concrete with low strength and low
stiffness will absorb more energy to yield in a lower rebound value.
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53. Rebound Hammer Test
• The results are significantly affected by the following factors:
a. Mix characteristics:
i. Cement type,
ii. Cement Content,
iii. Course aggregate type:
b. Angle of Inclination of direction of hammer with reference to
horizontal
c. Member Characteristics,
ii. Compaction,
iii. Surface type,
iv. Age, rate of hardening and curing type,
v. Surface carbonation,
vi. Moisture Condition,
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54. Rebound Hammer Test
Average Rebound Quality of Concrete
>40 Very Good
30-40 Good
20-30 Fair
<20 Poor and/or delaminated
0 Very Poor and/or delaminated
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56. Ultrasonic Pulse Velocity Test
The ultrasonic pulse velocity method basically involves the
measurement of velocity electronics pulses passing through concrete
from a transmitting transducer to a receiving transducer. The density
and elastic properties are in turn related to the quality and the
strength of material. The pulse velocities ranges from about 3 to 5
km/s.
An Ultrasonic pulse apparatus consists of a transmitter and a receiver
which are held again two faces of concrete. The apparatus generates
pulses of ultrasonic frequency which are transmitted through
concrete by the transmitter. On the other face, the receiver receives
the pulses and the apparatus records them. The time of travel
between initial onset and the reception of the pulse is measured
electronically. The path length between the transducer and the
receiver, divided by the time of travel gives the average velocity of
wave propagation. The velocity of pulses is correlated to the strength
of concrete. Higher the velocity of pulses greater the strength of
concrete.
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57. Ultrasonic Pulse Velocity Test
Pulse Velocity Concrete quality
> 4.0 km/s Very good to excellent
3.5-4.0 km/s Good to very good, slight porosity may exist.
3.0- 3.5 km/s Satisfactory but loss of integrity is suspected
<3.0 km/s Poor and loss of integrity exist
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58. Penetration Resistance (‘Windsor Probe’
and ‘PNR Tester’)
The determination of the resistance of concrete to penetration by a steel
rode or probe, driven by a fixed amount of energy can be assess the
compressive strength of concrete. The Principal is that, the depth of
penetration is inversely proportional to the compressive strength. The
relation between strength of concrete and the depth of penetration
greatly depends on the hardness of the aggregate because the coarse
aggregate particles become fractured in the penetration tests.
This technique offers a means of determining relative strengths of
concrete in the same structure or relative strength of different structures.
Because of the nature of equipment, it can not, and should not be
expected to yield absolute values of strength. ‘Windsor Probe’, as
commercially known, is penetration resistance measurement equipment,
which consists of a gun powder actuated driver, hardened alloy rod
probe, loaded cartridges, a depth gauge and other related accessories.BITS Edu Campus
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59. Penetration Resistance (‘Windsor Probe’
and ‘PNR Tester’)
In this technique, a gunpowder-actuated drivers used to fire a
hardened alloy probe into the concrete. During testing, it is the
exposed length of probe, which is measured by a calibration depth
gauge.. Being a low energy device, sensitivity is reduced at higher
strengths. Hence, it is not recommended for testing concrete having
strength above 28 N/sqmm. The penetration of pin creates a small
indentation (or hole) on the surface of concrete. The pin is removed
from the hole, the hole is cleaned with an air jet and the whole depth
is measured with a suitable depth gauge. Each time a new pin is
required as the pin gets blunted after use. The strength properties of
both mortar and stone aggregate influence the penetration depth of
the probe in a concrete. It is claimed an average coefficient of
variation for a series of groups of three readings on similar concrete
of the order of 4% may be expected.BITS Edu Campus
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61. Pull out Testing
As the name suggests, this method involves the measurement of the
force required to pull out a specially shaped steel rod or some similar
device from a concrete surface. There two basic categories one which
involves an insert having to be cast into the concrete is called cast-in
method and another where the insert is fixed into a hole drilling into
hardened concrete is called drilled hole method and it is more
appropriate for field survey of hardened concrete.
1. Cast-in Method (LOK Test):
The main aim of this technique is to measure the tensile force required
to pull-out the a metal insert which has been cast into the fresh concrete.
This test is commercially known as LOK-test. In this system the insert is
directly attached to the formwork. The basic geometry of insert contains
25mm diameter disc attach to a removable steam which locates the disc
25mm below the concrete surface. To prevent the disc rotating when the
stem is being removed a 15mm notch is provided on one side of the
disc.
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62. Pull out Testing
The load is applied to the disc through a removable pull-bolt using a
hydraulic jack which has a constant loading rate. From the peak tensile load
recorded by the jack the cube compressive strength is estimated.
2. Drilled-hole method (CAPO Test):
It is observed that one of the main limitations of the cast-in method was
that the inserts needed to be place before or at least during concreting
process. To overcome this problem another type of pull out test was
developed which would be completed on existing structures. The basic
geometry of this is same as the cast-in method. The main advantage of this
method is extremely valuable for in situ strength assessment. The CAPO is
based on the expression cut and pull out. The basic procedure for this test
consists of drilling a 45mm deep, 18mm dia hole after which a 25mm dia
groove is cut at a depth of 25mm using portable reaming machine.
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63. Pull out Testing
An expanding ring is than placed and expanded into grove using a pull bolt
assembly. The convenient LOK Test pulling equipment is then attach to the
pull bolt continues until the cone of concrete is removed to allow retrieval
of the pull bolt.
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64. Chemical Test
Some of the chemical test are as follows:
Depth of carbonation
Chloride content
Cement content
Sulphate content
Alkali content
1. Depth of carbonation:
This test is carried out to determine the depth of concrete affected due to
combines attack of atmospheric carbon dioxide and moisture causing g
a reduction level of alkanity of concrete.
A spray of 0.2% solution of phenolphthalein is used as pH indicator of
concrete. The change of color of concrete to pink indicates that the
concrete is in a good health, where no change in color takes place, it is
suggestive of carbonation affected concrete.
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65. Chemical Test
The i-situ test is conducted by drilling a hole on the concrete surface
upto cover concrete thickness, removing dust by air blowing spraying
0.2% solution of phenolphthalein with physician’s injection syringe and
needle on such freshly drilled concrete and observing the color change.
2. Chloride content:
It is important to know the level of chloride near the steel concrete
interface. Chloride present in concrete are fixed as well as free. Though
it is free chloride ions which are importance from corrosion risk point of
view. Chloride contents are determined and compared with the limiting
values specified for the concrete to assess the rise of corrosion in
concrete.
As per IS code the test consists of obtaining powdered samples by
drilling and collecting from different depths ie 5mm and mixing the
sample with a special chloride extraction liquid and measuring the
electrical potential of the liquid by chloride ion sensitive electrode.
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66. Corrosion Assessment (test)
1. Cover meter survey:
The main purpose of providing concrete cover to reinforcement is to
protect it from corrosion. A Cover thickness survey is useful to
determine existing cover thickness in a specific location where a
damage has been identified and elsewhere for comparison on same
structure. A cover meter is use to measure the thickness of cover, dia of
rebar and spacing of rebars.
2. Half cell potential survey:
The corrosion of steel in concrete is an electrochemical process.
Depending on the corrosion activity the electrode potential of steel rebar
undergoes changes with reference to a standard electrode. By making
measurements on well defined grid points over the whole surface, a
distinction can be made between corroding and non-corroding locations.
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67. Corrosion Assessment (test)
The various standard electrodes used are:
Copper-copper sulphate electrode
Silver-silver chloride electrode
A reference electrode is connected to the rebar and voltage difference is
measured between the rebar and the reference electrode. Generally, the
voltage potential becomes more and more negative as the corrosion
becomes more and more active.
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68. Fire Damage Assessment
The current practice is to assess fire rating of building rather than fire
resistance of materials although fire resistance has a significant
contribution to fire rating.
Generally fire resistance of a material or fire rating of an element
depends on:
Properties of materials
Temperatures generated during fire
Duration of fire exposure
Concrete can resist fire up to about 200-300 degree Celsius. It is non
combustible material and does not give out smoke or fumes when
expose to fire.
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69. Fire Damage Assessment
The factor affecting the fire resistance of concrete are:
1. Type of aggregate: Igneous stone aggregate will be more stable
against fire. Light weight aggregates offer vary good fire resistance.
2. Lean Concrete: Lean concrete having low cement content show
better resistance to fire.
3. Admixtures: Concrete with admixtures like fly ash, ground furnace
slag also have better fire resistance.
4. Moisture content in concrete: Moist concrete disintegrates faster
than dry concrete.
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70. Fire Damage Assessment
DTA- Differential Thermal Analysis:
This technique is use to study the physical and chemical changes that
occur in a material when it is heated. It is concerned with the rate of
change of temperature of a sample as it is heated at a constant rate of
heat flow. Its principle is based on “when a material is slowly heated its
temperature rises but when the material undergoes any endothermic
reaction ie losing water, losing carbon dioxide its temperature remains
constant.” In DTA study the sample and an inert material are heated
separately and the difference of temp between the two is recorded by
means of thermocouples which generated an electrical signal whenever
there is temp differences between the reference and the sample. When
there is no endothermic reaction in the sample there would not be any
differences of temp between the reference and the sample and hence no
electrical signal would occur.
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71. Fire Damage Assessment
The results of DTA are presented in the form of DTA curves. The
occurrence of any pulse appears as a peak in the DTA curve which is a
plot of temp versus electrical signal generated. Qualitative composition
of the sample can be judged by measuring the size of the peak in the
DTA curve. The peak size is directly related with the amount of heat
involved in the transition.
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