Repair & Rehabilitation: STP Ltd

Hasan Rizvi, STP Ltd
Hasan Rizvi (Sr. VP STP Ltd)

STP provides Waterproofing & Protective Coating solutions for all areas. The range of waterproofing coats consists ShaliRust Off, ShaliPrime ZnR, ShaliBond concrete, Shalifix EM, ShaliGrout EI, ShaliFix RM, ShaliCryl 215.


The three major signs of distress in a concrete structures are cracking, spalling, and disintegration. To achieve durable repairs, it is necessary to consider the factors affecting the design and selection of repair systems as parts of a whole, or as components of a composite system.

Cracking is one of the most misunderstood problems of concrete, as it is generally regarded as indicative of defective design or materials. Methods of repairing cracks include bonding with epoxies, routing and sealing, stitching, external stressing, grouting, blanketing, use of overlays, etc. Repairing cracks does not usually involve strengthening. In a structure showing spalling and disintegration, it is usual to find that there have been substantial losses of section and/or pronounced corrosion of reinforcement. Hence, the repair involves some requirement for restoration of lost strength.

Development of cracking in concrete is due to tensile stress and can be arrested by removing these stresses. Further, the cracks can be closed by inducing a compressive force, sufficient to overcome the tension and to provide a residual compression. The success of repair and rehabilitation of a structure depends on the specific plans designed for it.

STP repair

Repairing cracks in concrete structures

Protection, Repair and Rehabilitation procedures depend on evaluating the condition of concrete in the structure; relating the condition of the concrete to the underlying causes of distresses; selecting appropriate repair materials and methods for any deficiency found; and using the selected materials and methods to repair or rehabilitate the structure.

The following factors affecting the durability of structures should be taken into account for both new concrete constructions and for deteriorated structures:
  • Quality of construction
  • Lack of waterproofing treatment
  • Poor maintenance, blocked drain pipes
  • Lack of proper slope causing stagnation of water
  • Leaking pipe joints.
The compatibility of materials in repair systems and the increased need for performance specifications are important considerations. A holistic model for deterioration takes into account the effect of both the scientific facts and the experimental knowledge of environmental factors, and how they affect each component of the structure. To achieve durable repairs, it is necessary to consider the factors affecting the design and selection of repair systems as part of a whole or as components of a composite system.

The reason why repairs fail is due to improper understanding of the structure and causes of the distresses. Once the reasons are identified, a proper repair strategy can be worked out by a qualified civil engineer.

Penetration of corrosive substances leads to further corrosion of the steel reinforcements. As the rust has more volume then the original steel bar, the rust causes tension in the surrounding concrete. As the cover of concrete is limited on the outer side, the resultant tensile force causes crack formations, and the cracks permit easier entry of water and oxygen to form more rusting, resulting in increase in the volume and size of the cracks, which get wider and wider. As a result of this, the surrounding concrete becomes partly disintegrated, which finally causes spalling.

Repair of a township with severe spalling

Repair involves:
  • Removing all the damaged/cracked/spalled concrete by tapping with light hammer/chipping with chisel/high pressure water jets/compressed air
  • Cleaning and removing all loose and defective concrete/materials
  • Cleaning all the corroded/rusted reinforcement bars upto 28 mm diameter
The above can be achieved by the following processes:
  • Using rust remover ShaliRust Off of STP
  • Mixing extra reinforcement as required by welding
  • Applying epoxy resin-based approved make of primer ShaliPrime ZnR of STP
  • Applying a single coat of epoxy resin-based bonding agent ShaliBond concrete of STP
  • Fixing standard injection nozzles of 10/12 mm diameter
  • Including drilling holes of required diameter for the nozzles at 300mm spacing along the crack
  • Sealing the nozzle from sides with epoxy mortar Shalifix EM
  • Injecting through the fixed nozzle epoxy injection resin grout ShaliGrout EI of STP
  • Applying pre-packed cementitious patch repair mortar ShaliFix RM of STP
  • Applying surface protection, exterior paint coating ShaliCryl 215 of STP
Conclusion

Proper application of material is one of the most important aspects of any repairing process. STP Ltd has been involved in the Repair & Rehabilitation of numerous structures. The company has also set up the STP Institute of Waterproofing & Protective Coating for training applicators, so that they are capable of diagnosing problems and using the right materials in the right way.

NBM&CW February 2018

Long lasting waterproofing solution with Epoxy and PU

Atul Ltd's Lapox® epoxy range of adhesives find the largest application in the construction sector. Products include Lapox® Lacrete and Lapox® Procoat for terrace waterproofing; Ultrafix for vertical cladding Read More ...

The Raincoat Advantage

In heavy monsoons, would you be caught wearing a torn canvas jacket? Of course not, what a ridiculous question! You would wear a raincoat. So why not extend the same logic to the building structures Read More ...

Roads & Bridges: Repairing, Waterproofing & Asset Management

Waterproofing Technology is continuously progressing. In this context, several important concepts are illustrated which are of use to technology planners and forecasters. STP Ltd has one of the biggest Read More ...

STP offers Green and Cost-Effective Solutions for Road Construction & Maintenance

Fiscal year 2016-17 started with big reforms and multi-dimensional growth-oriented measures like budget allocation for infrastructure developments, over 10,000 km of roads, waterways, railways, and Read More ...

Black Bond Seal Black Concentrated Resin for Multiple Applications

Bond Seal India Pvt. Ltd. is meeting the demand in the construction industry for protection, maintenance and restoration by offering the right solutions and quality products, and innovating for the future Read More ...

Trelleborg launches Rotary Seal for equipment working under high pressure

Trelleborg Sealing Solutions
Trelleborg’s Turcon® Roto Glyd Ring® V rotary seal is designed for equip to work under high pressure without compromising the sealing performance. Trelleborg Sealing Solutions launched an innovative Read More ...

Polygomma™ EPDM Waterproofing Membranes for various areas of building

Polygomma
EPDM Waterproofing Membranes by Polygomma™ are easy to install and can be used on various areas of a building including basements, podiums/landscape areas, roofs/terraces, wet areas Read More ...

Buildtech offers high quality Liquid Waterproofing Membranes

Buildtech
BUILDTHENE IC-Polyurethane-based & BUILDCOTE EC 20-Acrylic Polymer-based Liquid Membranes are the two new waterproofing products by Buildtech. Buildtech is a trailblazer in the Construction Chemicals Read More ...

STP’s Waterproofing & Coloring Solutions for Roads & Bridges

Shali Seal RSTC Elevated Roads
STP's waterproofing soultions include ShaliSeal RSTC, SuperThermoLay APP membrane, ShaliSeal CSS, ShaliPatch, ShaliPatch EC, to be used on Roads & Bridges. Waterproofing Technology is continuously Read More ...

Crystalline Technology vs. Densification Technology

Crystalline Waterproofing Systems
In the current construction materials marketplace, crystalline waterproofing systems have been steadily gaining acceptance as a superior long-term method of providing effective concrete waterproofing Read More ...

Goodwill’s product for repair & maintenance- Fiberfix

FiberFix Repair Maintenance
Goodwill Retails Private Limited introduces Fibrefix to deal with leakage and breakage in pipelines during construction/repair work. Dealing with chemicals often causes leaks and breaks in pipelines Read More ...

Waterproofing of Roads & Bridges, Repairs & Making Coloured Roads

ShaliSeal RSTC
In India, Infrastructure development is amongst the focused priorities of the government with large scale investments planned in both public works as well as private projects. Large scale highways and other Read More ...

Polygomma™ EPDM Waterproofing Membranes for Waterproofing of Basements

Polygamma EPDM Waterproofing Membrane
Polygomma manufactures world-class EPDM Waterproofing Membranes and Pond Liners. Ethylene Propylene Diene Monomer (EPDM) membrane is a single-ply rubber waterproofing membrane Read More ...

Interfacial Zones and Concrete Waterproofing by Buildcore Chemicals

Concrete Waterproofing
Waterproof concrete technologies can be as complicated as the pore and capillary structures within the concrete. There are many systems, ideas and theories on how to achieve waterproof concrete. Read More ...

Polygomma™ EPDM Waterproofing Membranes

Polygomma Waterproofing Membranes
Polygomma manufactures world-class EPDM (Ethylene Propylene Diene Monomer) Waterproofing Membranes and Pond Liners. EPDM membrane is a single-ply rubber waterproofing Read More ...

‘DURAfloorguard’ Guards Against Industrial Flooring Damage

Durafloorguard
Protection of floors in industrial units is often neglected due to lack of knowledge about its significance and also due to the fact that it is not treated as part of the core industrial activity. But often damaged floors Read More ...
NBM&CW

New Building Material & Construction World

New Building Material & Construction World
MGS Architecture

Modern Green Structures & Architecture

Modern Green Structures & Architecture
L&ST

Lifting & Specialized Transport

Lifting & Specialized Transport
II&TW

Indian Infrastructure & Tenders Week

Indian Infrastructure & Tenders Week