Roles and Responsibilities of a Consulting Civil Engineer

A consulting civil engineer is an independent, professional engineer who performs well-detailed engineering services for clients on agreed sum of money.

It is quite unfortunate that the services and responsibilities that a consulting civil engineer renders are poorly understood while those who seek to engage him have only a vague idea of his functions. Most graduates of engineering background also have a meager understanding of the role he plays. Even some consulting civil engineers lack adequate comprehension of their responsibilities and obligations.

This article is presented to address all of the above shortcomings and to make the public at large appreciate the works of a consulting civil engineer. I have drawn mostly on my experiences as a professional engineer who has worked with both governmental and corporate organizations on various landmark projects.

Consulting is not a field for a person who hesitates to face new challenges. The competent engineer who likes variety and enjoys the challenge of ever-changing problems can find a fascinating and rewarding career in a consulting firm.

The profession demands business and management skills in addition to engineering and professional trainings. It offers a unique opportunity for self-employment and it is perhaps the only path open to an engineer with the spirit of an entrepreneur who wishes to become his own boss in full-time engineering practice.

In spite of its importance, challenge and fascination, the profession of consulting engineering is little recognized and poorly appreciated by members of the public largely due to the fact that his services are seldom performed for individuals as in the case of other professions like medicine and law.

Roles and Responsibilities of a Consulting Civil Engineer

The types of services performed by consulting civil engineers are outlined and discussed below.

Consultation

Consultation occurs when a client, who needs an opinion on some engineering problems, avails himself of the expert knowledge and the experience of a consulting civil engineer. Consultations may be brief or extended and may sometimes require considerable travel and a substantial portion of the consultant’s time.

Investigation

Most consultations usually require some study and investigation which involve analysis and simple computations while others may require field trips to observe and inspect equipment or structures. Still again, they may involve a review of studies, reports, investigations or communications prepared by other engineers or by the client’s management.

Feasibility Reports

These reports are concerned with determining the feasibility of some projects while presenting the results of surveys, studies and investigation carried out to confirm the engineering solution to be adopted in line with the financial cost. A feasibility study will usually include such items as purpose of study, requirements and needs of project, alternate solutions, estimated construction cost, recommendations and conclusion.

Engineering Design

Engineering design is the process of determining the physical characteristics and dimensions of a structure or project to be constructed or manufactured. These characteristics and dimensions are presented graphically on drawings, commonly referred to as blueprints by the layman. Such drawings, or plans, are supplemented by written documents called specifications.

Plans and Specifications are used to direct the contractor or the manufacturer on the details of work expected from him. Frequently, the design process includes the preparation of detailed lists of materials called bill of quantities which is used to procure all the materials needed for the construction or manufacturing work.

Procurement

The consulting civil engineer often assists the client in the selection of contractors or in the purchase of materials for the award of contracts. Procurement usually involves the receipt of a proposal from one or more material suppliers and selection is made on a competitive or a negotiated basis.

On construction projects, particularly for government organizations, contracts are usually awarded on the basis of competitive bidding while the engineer will normally prepare the contract documents in addition to drawings and specifications in conjunction with the client’s legal officer.

With the plans, specifications and contract documents, bids are solicited from contractors or manufacturers through public notices issued in accordance with legal requirements. After the receipt of all interested tenders, bids are opened publicly, as a rule, read and tabulated by the consulting civil engineer who will then makes his recommendations to the client.

Construction Supervision

This activity consists of two parts – general supervision and resident supervision. General supervision involves the following:

a) Periodic visits to site

b) Consultation with the Owner/Client

c) Interpretation of plans and specifications

d) Checking working drawings and data

e) Processing & certification of contractor’s payment estimates

f) Preparation of amendments to contractor’s contract

g) Final inspection of project

h) Preparation of “as-built” drawings

Resident supervision however requires the consulting engineer to send a representative or a resident engineer to the site of the project. The resident engineer is responsible for detailed supervision and inspection to ensure that the project is constructed according to the plans and specifications. In addition, he also coordinates and expedites the activities of the contractors.

Roles and Responsibilities of Structural Design Engineers in Construction

Structural design engineer performs various roles and responsibilities in a construction project providing technical details for the activities to be performed at construction site.

Structural engineering is a wider discipline under the field of civil engineering. It is a vast topic with unlimited theories and practices. It’s a field that is still developing with huge innovations and ideas.

So being a structural engineer, the roles and responsibilities that have to be received is of greater importance.

The structural engineering is more concerned with the design and the physical integrity of the structures. These structures can be buildings, dams, tunnels, bridges etc.

The main focused responsibility of a structural engineer is to bring a structure that will ensure safety and durability till the service period.

The architects develop building only based on the size, shape and use of the building. But these have certain hidden technical issues during construction and after, that can be found and resolved only by the structural engineers. The structural engineers help the architects to achieve his or her vision of the project planned.

Roles and Responsibilities of Structural Design Engineers in Construction

A strong knowledge of physics, creative problem solving and three-dimensional conceptual skill must be gained by a structural engineer. Other than these, the roles and the responsibilities of the structural engineer includes:

1. Structural Designing
2. Site and Work Investigations
3. Communication
4. Construction Management
5. Adequate Training

Structural Designing

Structural engineers are more graduated for structural detailing and their analysis. So, they are more in to design of structures. The structural designing procedures carried out by the structural engineers include calculating the loads and the stresses acting on the building, analysis for the loads, design of sections of structures to sustain the loads; so that the structure designed will withstand the loads predicted safely.

The structural engineers are also involved in the selection of materials best suited for the structure. This will hence ask for good knowledge about the different materials that are used in the construction at the current condition like their economic factors, strength factors and durability factors.

The quality factors of different building materials can be analyzed by a structural engineer to finalize their suitability in the design of the beams, columns or the foundations.

Another skill of a structural designer is the analysis of structures. This is presently carried out by the software like ETABS, STAAD, SAP etc. As years pass new software are being developed for the analysis of structures at different conditions of loads like wind, earthquake etc.

Most of the structural engineers have to study and work with these software with a knowledge of both the technical details and the programming details. In some organizations, the analysis is carried out by a programmer who may not have the civil engineering graduation but is assisted by a structural engineer.

Whatever be the mode of analysis done, the structural engineer must have the ability to understand and interpret the results from the software to know the validity of the values provided as output. Some organization won’t completely rely on the computer results, they conduct a separate man-made calculation for assurance.

Site Investigations

When dealing with the site investigation, the structural engineers are involved in checking the condition of the soil for the construction of the project. Based on the loads calculated by the designer, it must be checked whether the soil is suitable to bear the calculated loads.

This investigation will also decide the foundation systems that must be used for the structure. Any kind of treatment required for the soil too is decided based on the investigation. This investigation is carried out by testing the soil which is the part of geotechnical engineer.

Communication

Even though structural engineers are the ones that bring and develop the design ideas and detail, he can only see it happen on the site only if the structure is constructed as desired. For this, his interpretation and ideas have to conveyed with the other members of the projects.

The structural engineer has to coordinate and consult other members like the site engineers, other design engineers, geotechnical engineers, landscape architects, architects, project managers etc. Proper knowledge helps in spreading correct information among the group avoiding confusion and errors.

Construction Management

The management responsibility of a structural engineer starts from the collection of sufficient information for the project to the execution of different activities on the construction site. In certain critical situations, they are responsible for material and equipment delivery for undergoing a special task of the construction project. They conduct frequent checks of the on-site labor works and the activities.

Training Works

Not all structural engineers are trained for the complete responsibilities. Some are gained through years of experience and some standard skills through different training activities. As construction is an industry prone to more of safety issues, structural engineers are to be trained for strict standards of working.

Organization authorities can train the structural engineers for special quality certifications or for special analysis or design software. Proper knowledge of the National codes of the area is an important technical knowledge for any structural engineer.

Roles and Responsibilities of Architect in Construction

Architects in construction plays an important role and they are responsible for visual appearance of the buildings and structures before final structural design.

Architect is a person appointed by the client, who develops a facility as per the design concept and the requirements specified by the client. The architects develop design that are more creative in aesthetics.

The architect makes use of vision and creative ideas to satisfy the client. But the design evolved by the architects have to satisfy with the building laws and the regulations of the state.

Role of Architects in Construction

An architect both artistic and functional mind for the design of structures. Once an architect is approached by a client or a sponsor, he calls a meeting to know the needs and the wants of the construction work or project.

The building is designed by the architect that will satisfy the client. The architect brings more of creativity and artistic elements on the building. This creation of design will be repeated till both the parties i.e. the client and the designer are satisfied.

Responsibilities of Architects in Construction

The work carried out by the architect have to be properly organized. This demands to keep the records of different contracts, the details of the project, the cost and the budget details, the time limit and the day by day progress report.

Most of the cases the architects have to work with the civil or structural engineers for communication and discussion relating the technical issues faced in the design and the implementation.

The key responsibilities of an architect in construction projects are mentioned below:

Role of Architects in Project Discussion

Meeting and discussions have to be kept with different members and professionals of the organization before approval of the project design. This helps in realizing different technical difficulties that would be faced, opinions and economical ideas. This can help in moving the team together for the completion of the project.

The project discussion carried out by the architect includes the following works:

• The initial step involves understanding the client’s requirement through a detailed discussion. A careful note on his/her objectives and the expectations are taken.
• Quantifying and qualifying the project will involve the discussion about the expected budget, the characteristics of the site and other planning regulation of the area under consideration.
• Next is the difference sequence of operations, guarantees, and responsibilities offered by the architect. This will include:
  • Understanding the limitations and potential of the site.
  • Discussing about the financial targets
  • Suggesting and studying all possible solutions if the work is renovation or rehabilitation or a new construction
  • Bringing and presenting the feasibility study
  • Different choice of site or building based on the requirement
  • Provision of different options to overcome different administrative procedures
  • Procedures planned and prepared are kept in line to make communication easier.

Role of Architects in Preparation of Drawings

A construction project has enormous design drawings that have to be prepared all before the execution of the work on site. Any errors have to be pre-checked before implementing it.

This early submission of drawings helps in avoiding the delaying of the project. The drawings are the basis on which detailed estimation, material procurement and work at site is carried out.

Initially, the sketch designs are prepared which will shows the building location. This gives an idea about the layout of different spaces within and nearby as well as different links to the site. The overall massing and the appearance of the project too is reflected on the sketch design.

The sketch design is the basis on which the client agrees to certain principles and agreements. The end of sketch design will follow the contract proposal that will move to the next phase of cost estimation and the timescale of the project.

The construction of a building or a structure is now performed by both the architect and a civil engineer provided they have adequate experience and skill. The different drawings an architect can render will include the floor plan, the site plan, the elevation and the isometric vies, Other detailed structural drawings, 3D models and 3D views.

Mainly these works or details provided by the architect will depend on the work provided to him. Sometimes there comes situations where we have a structural designer to design the plan and the structural building.

We need to have a good elevation for the given plan. Here, we will approach the architect to deal with the front elevation and the landscaping details. This will hence ask for cooperation and discussion between the engineer and the architect.

Safety Precautions at Construction Site

Any construction site is a dangerous occupation for all personnel, especially for labors working on site and so one must be prepared every day for safety. For this purpose, various safety measures have to be taken.

Safety Procedures at Construction Site

Personal protective equipment (PPE) are supplied to all the personnel’s working on site and even for the personal who are temporary visiting to the site.

Personal protective equipment (PPE) can be classified as:

• Minimum Personal protective equipment (PPE)
• Additional Personal protective equipment (PPE)

Minimum PPE Requirements for Safety at Construction Site

Hard Hat or Helmet

Hard hat or helmet is issued to each and every personnel working on site. It has to be worn all times at job site.

Safety Glasses

Safety glasses are required at construction site every time debris is filled in air due to activities on site.

Hand Protection Gloves

Hand gloves are supplied to all personals to protect against cuts when handling material or equipment’s, during cleaning operations, cutting metal studs or similar works.

Safety Vests

Safety vests also called as high visibility shirts. Purpose of safety vest is to keep the person always clear in view, even in the dark and he should be visible to everyone.

Safety vests are of different bright colors like red, green, yellow so it’s easy for workers to see and locate each other

Proper Clothing

Shirts, long pants and hard soul shoes, a 6-inch-high boot is recommended.

Additional PPE Equipments for Safety at Construction Site

Hearing Protection

It is compulsory to wear hearing protection equipment near any equipment, tool or machinery which makes loud noises. As per standard practice if you are 2 foot away from somebody and you need to shout to talk, putting hearing protection is necessary.

Respiratory Protection

Sometimes as voluntary respiration policy dust mask is supplied, any employee looking for additional comfort or safety while working with fiber glass, fire proofing, cleaning the floors or handling debris.

Face shields

A full face shield should be worn along with safety glasses when working in a high debris, operating grinder or any spark producing activity or similar activities or when done on site. An approved welding shield is compulsory to wear during all welding operations.

Safety Harness

The safety harness is an attachment between a fixed and mobile object and is usually fabricated from rope, cable and locking hardware.

Full body safety harness to be used as a procedure for fall protecting system, ignorance can result in severe physical harm. Safety harnesses keep workers safe and are helpful in freeing their hands for work even while hanging on the side of a building.

Material Storage

Material on the job site should be stored properly when not in use to prevent injury and wastage of materials. Ensure proper storage and good housekeeping.

Proper storage can prevent the falls of the materials leading to material damage and accidents. Weight of the material stored should be within safe loading limits of the building floor.

Keep the passageway always clear for walking of personal and prevent injuries. Always store the material away from traffic.

Store material at least 6 feet away from the openings in the floor and 10 feet from the edge of the floor if the wall is not built on edge of floor.

Manual Material Handling

The personnel should be aware of his weight lifting capacity and if required take the help of another person if required instead of taking all load himself and use proper lifting techniques. Always need to wear the safety equipment’s while working on construction site.

Mechanical Material Handling

Mechanical material handling also requires same amount of safety as in case of manual material handling. Equipment Operator needs to take care of the weight lifting capacity of the equipment like forklifts, cranes and other similar to avoid accidents.

Ground personnel should be in machine operator’s vision always and should be aware of the safety procedures while working around the heavy mechanical equipments.

Basic Safety Precautions at Construction Site

In any construction project for basic safety precautions to be implemented are:

• Guard rails to be installed at open scaffold areas, all openings in the building floor, in the excavated areas, at mobile elevated platforms.
• Yellow stickers with safety notes to be pasted where necessary
• All the working platforms should be stable, properly braced, should not be overloaded and safe for the working personnel
• All the working areas and passageways should be free from waste or debris or any of obstruction like stored material
• The site should be clean all the times and the material should be stored safely
• There should be proper arrangement of collection and disposal of waste materials
• First aid should be available at all times on site for cuts burns or any mishaps
• Fire extinguishers to be placed on site on proper locations in case of any fire
• That should be proper lighting arrangements on the site especially when the work is carried out during the night stand

To summarize, world class construction project execution is impossible without proper health and safety management

Repairs and Rehabilitation of Concrete Structures for Failure and Defects

There are various techniques available for repair and rehabilitation of concrete structure for failure and defects in concrete. These techniques and materials for repair of concrete is described.

Concrete is the most widely used and versatile construction material possessing several advantages over steel and other construction materials. However very often one come across with some defects in concrete. The defects may manifest themselves in the form of cracks, spalling of concrete, exposure of reinforcement, excessive deflections or other signs of distress.

On many occasions, corrosion of reinforcement may trigger off cracking and spalling of concrete, coupled with deterioration in the strength of the structure. Such situations call for repairs of affected zones and sometimes for the replacement of the entire structure.

Causes for Failures or Defects in Concrete Structures

The following are the major causes for failures of concrete structures:

• Structural deficiency arising out of faulty design and detailing as well as wrong assumptions in the loading criteria.
• Structural deficiency due to defects in construction, use of inferior and substandard materials, poor workmanship, and negligence in quality control and supervision.
• Damages caused due to fire, floods, earthquakes, etc.
• Chemical deterioration and marine environments.
• Damages caused due to abrasion, wear and tear, impact, dampness etc.
• Movement of concrete caused due to settlement of foundation, thermal expansion etc.

Identification of Failures and Defects in Concrete Structures

A correct diagnosis establishing the cause, nature and extent of damage, and the weakness or deterioration caused in the structure is very essential, since a faulty diagnosis may lead to improper selection of materials and repair techniques leading to the failure of the repaired zone again. It may also be necessary that the serviceability of the structure is checked after carrying out the necessary repairs.

Need for Repair and Rehabilitation of Concrete Structure

The need of structural repairs can arise from any of the following:

• Faulty design of the structure
• Improper execution and bad workmanship
• Extreme weathering and environmental conditions
• High degree of chemical attack
• Ageing of the structure

Techniques for Repairs and Rehabilitation of Concrete Structure

The technique to be adopted for repair or restoration of the structure depends on the cause, extent and nature of damage, the function and importance of the structure, availability of suitable materials and facilities for carrying out repair, and a thorough knowledge of the long-term behavior of the materials used for the repair work.

Depending upon the requirement, the repairing technique may be of a superficial (cosmetic) nature or, in some cases, may involve the replacement of part or whole of the structure.

The repairing techniques can be classified into three major groups:

1. Injection into cracks, voids or honey-combed areas.
2. Surface treatment
3. Removal and replacing of defective or damaged material / area.

A variety of new materials have been developed for the repair and restoration of damaged structures by following any one of the above methods. These are briefly described below.

Materials for Repairs and Rehabilitation of Concrete Structure

Cement, Cement Grouts, etc.

In most cases, the repair material may be cement-based, since cement is the only active ingredient in concrete. Dry pack consisting of rich cement concrete or cement grouting may be suitable for sealing damaged areas and cracked portions.

Spraying of concrete or cement sand grout by means of high pressure nozzles, usually termed as ‘shotcrete’ or ‘guiniting’, respectively, may prove effective in many cases where a large surface area is to be repaired. The guiniting or shotcrete may be carried out with or without the use of steel reinforcing mesh or steel fibers.

Resin based Repairs of Concrete

The resins normally used are from epoxide, polyester, acrylic or polythene families. The application of resins for repair work requires a thorough understanding of their chemical and physical properties and their performance in the structure, particularly with the passage of time and under unfriendly environs.

Epoxy resin systems find application in civil engineering works such as grouting of cracks, repairs of eroded concrete structures, emergency repairs of bridges, aqueducts, chemically corroded columns and beams.

Generally, resin materials are used in repair and restoration work where properties such as, high strength (hence thin sections), excellent adhesion (hence small patches), quicker curing (hence saving in time), and high chemical resistance are required. One of the most commonly adopted resins is from epoxide. A brief description of the properties and applications of epoxy based resins is given below.

Epoxy Resins for Concrete Repair

The resin mortar may be obtained by adding fillers such as coarse sand or calcined bauxite grit. The chemical reaction begins as soon as the resin and hardener are combined. Most combinations have a pot-life between 30 and 60 minutes. They develop excellent strength and adhesive properties and are resistant to many chemicals besides possessing good water proofing.

Epoxy resin when cured with different hardeners offer wide range of properties. Once cured, they form irreversible system (thermosetting).

The characteristic properties of cured epoxy resin systems repair and rehabilitation of concrete structure are

• High adhesive strength to almost all materials
• Low shrinkage during curing
• Exceptional dimensional stability
• Natural gap filling properties
• Thermosetting (does not melt)
• Resistance to most chemicals and environments
• Ability to cure in wet conditions and underwater (for selected grades)
• Ease of application

Procedure of epoxy resin grouting

• Locating the cracks
• Cleaning of the cracked surface
• Drilling and fixing of nozzles for grouting at suitable intervals with epoxy putty
• Grouting of epoxy mixture with the help of the grout pump
• Sealing of nozzles through which grouting is done

A grout vessel essentially consists of a pressure vessel (to withstand 10 – 15 kg/cm2pressure) with inlet and outlet for resin mixture, pressure gauge, connection for compressed air with regulator for pressure grouting.

A pre-mixed resin + hardener is filled in the grouting vessel and through the nozzle the activated resin is pumped in the cracks. When cracks get filled in, the grouting is carried in the next nozzle and so on till all the cracks are filled in.

When cured, the epoxy resin improves the load carrying capacity of the cracked structure.

Bonding Old to New Concrete

Epoxy resin with a special polyamide hardener combination is successfully used for bonding old to new concrete.

The process consists of —

• Removal of all loose and damaged concrete using mechanical means or water jet
• Surface to be dried
• A suitable epoxy resin [unmodified solvent less epoxy resin + polyamide hardener (special grade)] is applied with stiff nylon brush
• The fresh concrete should be poured when epoxy coating has become just tack free
• Care should be taken not to completely dry the coating.

Epoxy resins are a not primary construction material. A judicious use of these resins is required in view of the high cost of these resins. The resins should be used in emergencies.

Properties of epoxy resin systems can be advantageously exploited, when other materials cannot be used due to strength or other considerations. Epoxy resins are finding many new applications in pressing conditions such as underwater repairs of dams, ships, etc. Many new applications will be found using epoxy and other synthetic resins in future.

Polymer Concrete Composites

Most of the deficiencies found in ordinary structural concrete are removed using polymer concrete composites either in the form of a surface coating over the structure or by impregnating it into the structure.

Polymer concrete composites are relatively new developments and have been used in structural applications since 1950. They possess very high strengths and are more durable and resistant to most chemicals and acids.

There are three types of polymer concrete composites, namely polymer impregnated concretes (PIC), polymer concretes (PC), and polymer cement concretes or polymer modified concretes (PCC or PMC). In PICs the monomers (usually styrene, methyl-methacrylate (MMA), polymethyl methacrylate (PMMA), etc.) are impregnated into the pore system of the hardened concrete, thereby filling up the pores and making them impermeable and resistant to chemical attack; In PCs the polymer is the sole binder in lieu of cement and water. In PCCs and PMC s, a polymeric additive (latex or pre-polymer) is added to the normal cement composite during the mixing stage itself.

All the three types of polymer concrete composites are useful for carrying out repairs and restoration work in damaged structures. The use of these composites for post-distress and post-failure applications is steadily increasing because of their superior durability, excellent bond to parent concrete structure, superior abrasion and wear-resistant properties, a high degree of resistance to chemicals like chlorides and acids, and their very low water absorption. Repairs of cracks can be easily carried out by injecting the polymer concrete damaged by corrosion of reinforcement can be chipped off and replaced by polymer concrete.

Sealants

Many commercial sealants are available for sealing of cracks in concrete structures. Joint sealants should ensure structural integrity and serviceability. They should also serve as protection against the passage of harmful liquids, gases, and other undesirable substance which would impair the quality of concrete. In the case of repair of a cracked surface, the cracks are first enlarged along their exposed face and are pointed up with the sealants.

Surface Treatment to Concrete

The durability of the concrete can also be increased particularly on the surface by applications of different materials which make it waterproof, hardened and resistant to chemical attack.

Some of the commonly used surface treatments are:

• Sodium silicate, magnesium or zinc fluoride
• Drying oils like Tung or Linseed oil
• Chlorinated rubber paints and neoprene paints
• Epoxy paints
• Silican Fluoride treatment

The surface of the hardened and dry concrete can be made abrasion resistant and less dust generating by application of solutions of sodium silicate, magnesium or zinc sulphates or silico fluorides. Drying oil like tung oil or linseed oil can be used. Alternatively, carborundum or fused alumina or finely divided iron aluminum chloride preparations may be added in the surface layer while placing the fresh concrete.

Floor paints also provide reasonable durability if the traffic on floor is not heavy. Paints containing synthetic resins particularly polyurethanes or epoxies or chlorinated rubber provide greater resistance to wear. They also protect against solutions of salts and dilute acids.

Sodium silicate and silico fluoride applications provide protection against mild conditions of attack by aqueous solutions or organic liquids. Bitumen and coal tar gives protection against insects and borers. Some plastic materials, rubber latex glass fiber coatings and PVC linings have also been successfully employed to improve durability of concrete.

Steel Fiber Reinforced Concrete

Use of small diameter steel fibers in concrete has been found to improve several properties of concrete and particularly its tensile strength and impact and wear resistance. One of the uses of steel fiber reinforced concrete (SFRC) is in the area of repairs and restoration of concrete structures.

The damaged portions of a concrete structure can be removed and can be made good by placing of SFRC to the sides and bottom of damaged structures by guiniting or shotcrete techniques. Because of its improved wear and tear and abrasion resistance, SFRC has been successfully employed for the repair of industrial floors and bridge decks with or without the use of polymer concrete.

Other Materials for Repair and Rehabilitation of Concrete

There are several other materials which can also be used for repairs of certain structures. For repairs to existing foundations, special chemical grouts have been developed which will ensure the compaction of the soil below and provides protection to the reinforcing steel in the foundations. Superplastized fiber reinforced concrete has been used in carrying out repairs to machine foundations and underground structures.

Certain chemicals and surface coatings marketed under brand names are said to seal the cracks in structures like water tanks and afford sufficient protection to the steel from corrosion. Special paints (latex or bitumen based) have also been developed for applying to the concrete surface or to the bars for making them resistant to aggressive environs.

With the increasing number of cases of damages being observed on structures built in the past, repairs and rehabilitation of such structures have assumed greater importance. Some of the techniques and materials found useful to reinstate some affected structures.

Table below shows the materials generally recommended for repair of concrete structures. Epoxy resins and concrete composites show high potential as promising repair materials.

Timely detection of deficiencies in concrete and steel of an existing structure and execution of immediate remedial measures will prevent further deterioration of the structure and will result in huge savings in the maintenance cost.

The old dictum, ‘prevention is better than cure’ is applicable to concrete structures, both at the time of constructing the structures and at a time when the structure has shown signs of initial distress.

Materials for Repair of Concrete

Repair Operation	Material	Comments
Sealing of fine cracks	- Epoxy resins	– Good bonding properties even in the presence of moisture
Sealing of large cracks and joints	- Portland cement Mortar - Polymer mortar - Putties and caulks	– Well – compacted – Good bonding properties – Based on synthetic polymers and tars
General sealing of surface	- Synthetic polymers and asphalt coatings
Localized patching of surfaces	– Concrete or mortar using Portland cement – Rapid-setting cements – Polymer resins; epoxies; polyesters	– Calcium aluminate and regulated-set cements – Good bonding
Overlays and shotcrete	– Portland cement concrete – Steel fiber reinforced concrete – Latex modified concrete – Polymer concrete – Asphaltic concrete	–Quick-setting admixtures – Resistance to cracking – Good bonding