Durability is a key requirement for modern infrastructure projects – highways and roads, bridges, airports and airfields, walkways and plazas, parking structures and stadiums. Miles of concrete must be designed to accommodate significant movement – especially in the joints – caused by unrelenting weather, temperature extremes, UV radiation and chemicals, such as de-icing materials and fuels.
It is a myth that waterproofing treatments can be carried out by application of single material on new concrete or existing treatments. There cannot be a single material that is right for every structure. Most of the failures in waterproofing are on account of this misconception. The only way to ensure reliable treatment is by considering the waterproofing treatment as a system. A System for Waterproofing can be defined as a combination of materials, preparation of specifications, application techniques designed by taking into considerations the requirement of the client or homeowner, which would provide efficient, reliable and long-term protection to concrete structures with minimum maintenance costs.
Kalpesh Chitroda, director, Maris Polymers, says, “Actually, now, the global trend is towards liquid polyurethane waterproofing systems. It is made up of two components, base and reactor. Polyol acts as the base, while isocyanide is the reactor component. The combination of both these in a specific design ratio creates a liquid coating for waterproofing applications. Polyurethane is a rather popular choice due to its ease of installation. Unlike other waterproofing systems like sheet membranes and liquid applied membranes, this polyurethane application requires comparatively less skill and supervision. Application is fast and this type of treatment can be used for post-construction applications as well.”
Today, the construction chemicals industry is developing a broad range of modern-day technologies using sustainable and durable materials. Polyurethane or silicone based sealants have now become the most common materials to provide long term effective sealing solutions for modern day infrastructure projects. Preformed expansion joint systems are also being developed for infrastructure projects such as bridges, airport hangers, etc. With the combination of fast drying times and advanced application tools, the infrastructure shutdown time is greatly reduced. This results in cost savings and increased profits. Bhooshan Dixit, head, product management group construction chemicals, Thermax, says, “With time, the construction chemicals industry is making constant advancements in material science as well as application techniques. Polyurethane or Polyurea based waterproofing systems are gaining more and more acceptance in the market. With the market shifting from bitumen membranes, high performance membranes like HDPE, PVC and TPO are being developed and used for waterproofing of critical areas. Repair and retrofitting products are being developed for seismic upgradation according to recent changes in the classification of seismic zones in our country. It has become imperative to keep developing new and more sustainable materials to keep up with the changes arising in new modern construction technologies. Our team has also been working on many more projects like injection grouting systems for infrastructure repairs, fire intermittent coatings for residential, commercial or industrial buildings. We hope in coming years we can provide our customers with the most versatile range of construction chemicals.”
Application areas
Waterproofing should never begin with a specific material in mind. The properties of material needed, are to be stated and then the material is to be selected as per the merit. To combat the different entry modes of water into concrete, a combined system of treatments is therefore necessary. To waterproof a structure completely, one has to address the 3 primary routes of entry into the structure, viz. pores, capillaries and voids in the concrete; joints and transitions; and cracks in the concrete cover.
These can be achieved by use of: admixtures and additives to reduce the porosity and capillarity in the concrete; treatment of joints, transitions and cracks using suitable coatings with reinforcement, flashing tapes and expansion joint tapes; and the cover concrete is to be protected by appropriate surface barrier coatings.
Chitroda says, “Different countries have different variations in temperature. Our buildings are mostly concrete. If you go to Canada, temperatures vary from 420 C to -200 C. They will update their construction technology to that particular temperature. We have a different challenge in India and think in which condition we are going to use this material and how we are going to achieve the waterproofing.”
India being a tropical country, we have all kinds of weather extremities; from heavy monsoon in some states to scorching heat and extreme cold in other states. “Structures in our country need to be protected from all types of weather abuse. Solutions working in other regions of the world may or may not work with such tropical weather. For e.g. due to abundance of oil in gulf countries, bitumen based products became popular but now people in India are realising that bitumen based products are not that suitable for our country. Waterproofing is surely one area which is of utmost concern in all types of weather environment. Choosing the combination of right product and system for your structure has become imperative. To find a good waterproofing system that provides not just protection against harsh rains but also sustains its system life under extreme heat or cold has become a constant topic of concern in India. Moreover, the concreting practices in India are different and admixtures need to be developed keeping in mind high retention time and scorching temperatures. We, at Thermax, realise this to be a major problem and are trying our best to provide best materials for countering this challenge,” says Dixit.
Samir Surlaker, director, Assess Build Chem, says, “InjectiontTechnologies have long been used to treat waterproofing issues. The areas of application of the suitable filling materials and filling methods depend mainly on the intended application goal, the crack width, crack movement, and dampness of the cracks/crack edges/crack flanks and voids. Usually three different injection systems/methodologies are specialized to solve critical waterproofing problems: grid injection [crack treatment or creation of a waterproof layer from the negative side]; water bar injection/expansion joint treatments/transitions; and injection hoses.
Specification is the key where most of the issues can be resolved beforehand. With the advancement of technology in every sector, users / clients have become more aware of the need and the benefits of good specifications.
