A round up on the most advanced material used for the construction of bridges and highways.

After going through such a bad phase in Indian construction industry, infrastructure development in the form of highways and bridge construction projects have shown a great sign of ‘BIG’ recovery. Have a look at what experts has to say in respond to the most advanced material being used in terms of Construction of bridges and highways.

KEM Mortar EP1
“There are lots of different products and solutions involved in bridges and highway construction. One amongst the other product range that Chembond has is KEM MORTAR EP1 which an epoxy based fair facing compound and concrete adhesive,” says Swapnil Deshmukh, Marketing Manager, Chembond Chemicals Ltd. He further adds, that KEM Mortar EP1 is solvent free, two component epoxy resin based thixotropic Mortar. The base component is white colored and the hardener is black to facilitate ease of mixing.”

The areas of application involved in KEM MORTAR EP1 are like filling blow holes, making fair slightly damaged concrete, eliminating minor irregularities prior to painting or coating. Even it’s been highly recommended for repair of structures that will be permanently submerged in water, sea water like water intake areas in power plants etc. Further, it also acts as an adhesive for bonding pre – fabricated concrete bridge segments.

Major benefits include:
The major advantages of KEM MORTAR EP1 are Non – sag, which can be applied to vertical surfaces and toweled into blow holes. Having paste like consistency, chemical resistant, excellent bonding to concrete surface, cures and hardens without shrinkage, hardening is not affected by high humidity. Moreover, high strength and e – modulus, can be applied from feather edge to 10 mm in horizontal application without form work, can be applied on damp substrates.

Dinesh Kumar, Executive Director, Millith Fibrex Technologies Pvt. Ltd. believes, Infrastructure development, nowadays is the backbone of Indian construction industry. “After going through a big down phase in Indian construction industry, infrastructure development in the form of highways and bridge construction projects have shown the signs of big recovery. Most of the projects are fast track, to set the pace with new govt. targets for early completions.”

Rehodynamic Admixture Technology – Fibcon
To achieve the faster progress, PCE based products have augmented the quick progress in highways and roads. “Millith Fibrex Technologies Pvt. Ltd. (A Fibrex Group Company) has come up with a new technology, based on PolyCarboxilate Cellulose system which we named as “Rehodynamic Admixture Technology – Fibcon,” Dinesh adds.

There is lot of variations in the sand; aggregates from single source and option of various cements make it a difficult task for quality control department to handle with. He also adds, “FIBREX group is poised to provide the new technologies, to counter the new local challenges faced time to time. Apart from providing normal workability vis-à-vis time duration, keeps the viscosity high and avoids particles and water to separate by maintaining the thixotropy of the mix constant.”

In addition, “The rehodynamic admixture technology, helps in taking the various changes under it dynamic behaviour and provides single solution of consistent concrete. The technology tested at various places and found reliable by user friendly,” states Dinesh.

According to Dinesh, “Other advantages or benefits from this available technology are –provide versatile solution under one system, helps to control low flow to very high flow, depending of workability requirements, durable concrete, without loss of green and hardened properties, apart from this it even offers better quality control, without loss of time and machinery efficiency along with better concrete finish etc.”

Speaking about the requirements for bridges, G.Ramdas, General Manager – Cera Chem Pvt Ltd, says “Due to the escalation in the repair and replacement costs of a structure, the attention is given to durability issues.”

Additive for Concrete
There is a demand for high tensile strength, compressive strength and durable structures to perform as per the expectations in various climatic and critical conditions. Ramdas says “This can only be achieved with the use of admixtures to the concrete mix.”

What determines the durability of concrete?
The selection of right quality raw materials and usage of reduced water cement ratio determines the density which leads to durability of concrete.

What determines concrete density?
Excess water results in void or capillary formation which can lead to durability problems. In addition to correct proportion of water, proper placing and compacting are necessary to ensure a watertight concrete.

Ramdas informs that Cera-Chem Pvt Ltd, have continuously worked to deliver innovative products keeping in mind Indian climatic conditions, incorporating new technologies and compatible raw materials, to satisfy all of our customer needs. Cera Crystalline Integral is one such product. “It is a crystalline based capillary waterproofing concrete admixture which acts as an integral part of the concrete.” he further states.

In rare conditions in spite of all the precautions, there are chances of ingress of moisture, water and other external influence leading to the corrosion of steel, bulging of concrete ultimately affecting the durability of the structure.

CERA COTE SP CI 100 is a corrosion inhibitor coating system, which penetrates into the concrete and inhibits electro-chemical corrosion process in all coastal steel reinforced structures exposed to relative humidity.

Ramdas feels that bridges and highways are one of the major life lines in connecting people. Keeping that in mind our R&D team has developed an admixture specifically for construction of bridges and highways. Further he stated, it is a unique combination of crystallization and corrosion inhibiting properties to achieve a water-tight concrete structure and simultaneously protect the reinforcement.

Sealants
A sealant is a viscous material that changes state to become rubber like compound, once applied, and is used to prevent the penetration of air, gas, noise, dust or liquid from one location through a barrier into another. Typically, sealants are used to close small openings that are difficult to seal with other materials, such as concrete, drywall, etc,” says Dinesh Chavan, DGM-R&D, Choksey Chemicals Pvt Ltd.
Uses of sealants vary widely and are used in many industries, such as construction, automotive and aerospace. “The main function of sealant is to improve thermal, absorption of the vibrations and prevent unwanted matter collected in the joints. The sealant must work as its prime function when it is subjected to repeated contraction and expansions as the joint opens and closes constantly while exposed to the weather conditions.” asserts Dinesh.

Polysulphide sealants
Dinesh feels that, Polysulphide sealants are the best sealants to be used for joint sealing. Moreover, the performance and durability of sealant always depend on the quality of sealants or some times on the design of the joint. Proper joint design and best quality sealant are needed for obtaining longer durability.

Dinesh informs “In case of roads or bridges, which are exposed to extreme weather, the concrete itself must be protected against the damage from all the possibilities of water at the joints openings. The solid material must be prevented from falling and collecting in the open joints if so the joints cannot contract freely later. If it occurs then high stress may be generated and can damage the concrete structure.”

“In case of highways, the joints are needed to be strengthened and sealed to prevent the damage from heavy traffic. Hence, the function of a sealant is to restrict the entry of water, solids, and gases and to protect the concrete structure from them,” concludes Dinesh.

“India has the second largest road network in the world, with approximate length of 49 lacs kilometre which caters to 80 per cent of country’s passenger traffic. The roads and bridge infrastructure industry is expected to be worth one lac twenty-five thousand crores in FY 2017-18,” says Sukanta Mallik, Asst.Vice President, CICO Technologies Ltd.

Mallik further states that, CICO offers a complete products basket for these particular sectors.

Admixture for concreting
Naphthalene Based:
These are the second generation concrete admixture based on a blend of specially selected organic polymers (SNF), combining the properties of super plasticiser with high degree of slump retention, and high range water reducing characteristics.

Naphthalene based products available with CICO:
• CICO Plast Super HS, CICO Plast Super HS-383, CICO Plast Super HS k-504, etc

PCE Based:
This is a new generation concrete admixture based on a blend of specially selected high molecular weight Polycarboxylate Ether (PCE) and proprietary organic polymers. Due to the robustness of this product, it can be used with all types of cement, fly ash, GGBFS, micro silica and any other cementitious products. It can be used with M-40 to M-80 grade of SCC as well as normal pump concrete.

PCE based products available with CICO:

• CICO Plast Super C-804, CICO Plast Super C-300, CICO Plast Super C-111, etc.

Curing compound for Concrete:
Curing compound whether a non membrane forming or a temporary membrane forming, will retain sufficient moisture inside the concrete for effective curing to take place. It can be wax, water, resin, aluminized resin based, etc. It is useful for large areas of concrete such as road carriageway, pavements, bridge decks etc.

Curing Compound Available with CICO:
• CICO Curefree SW, CICO Curefree C, CICO Ritecure AL, etc

Road Joints:
Polysulphide Sealant is a two component flexible joint sealer used to make the road joints water and weather resistant. Also these products accommodate the movement to prevent permanent deformation.

Road joints product available with CICO:
• CICO Sealant T680