Anil Banchhor, Chief Executive - Concrete Business at ACC Limited, Mumbai
ACC Set up the first commercial Ready Mix concrete plant in Mumbai in 1994. It Concrete is one of the largest Ready Mix Concrete manufacturers with a network of over 50 plants spread across all major cities in India. ACC's pioneering efforts in promoting use of ready mix concrete coupled with the promotion of bulk cement handling facilities have been responsible for redefining the pace and quality of construction activity in metropolitan areas and major infrastructure projects. The company has been at the forefront of sustainable construction in all the areas that it operates in.
In India, cement concrete roads were built in isolated locations on national highways, state highways and city roads since early 1950. In the last decade of the 20th century, few major road projects like Mumbai-Pune Expressway (90Km), Delhi-Mathura (100Km section), Indore bypass road (35Km) etc. were undertaken with concrete pavement. These experiences accelerated the construction of 1600Km concrete road under Golden quadrilateral. Further the advantages of cement concrete road over bitumen road in terms of longer life, less maintenance, good riding quality, better skid resistance, lower life cycle cost, no effect of rain water, no effect of spillage of oil, better reflectivity, saving in fuel consumption, etc. has also lead to construction of more concrete roads in several parts of India.
However, due to higher initial cost and the requirement of higher degree of care in design and construction, the concrete roads were not preferred over bitumen roads. Now the major road projects are being implemented using modern equipment, there has been substantial confidence and capacity building among the engineers and the contractors in the area of concrete roads. The cost difference between concrete and bitumen roads, which used to be over 50% earlier, has come down from 15 to 25% now. This gap has further come down to 10 from 15% due to adaptation of High Volume Fly Ash Technology in concrete road.
High Volume Fly Ash (HVFA) concrete was developed nearly two decades ago. In this type of concrete, about 40-60% of the Portland cement is replaced by a suitable quality of fly ash for different applications including concrete pavements. HVFA concrete exhibits improved fresh concrete properties and excellent mechanical properties and long-term durability along with economy.
Improvement in properties of HVFA concrete with respect to bleeding, setting time, autogenous temperature rise, development of compressive strength with age, flexural- and splitting-tensile strength, drying shrinkage, resistance to abrasion along with efficient use of cementitious material is leading the increased use of HVFA concrete in various applications in concrete constructions.
Good quality HVFA concrete can be produced with judicious use of cement and superplasticisers for different structural applications with varying percentage of fly ash additions. It can be used successfully in our country with very low life cycle cost and good performance, because fly ash is abundantly available and the temperature is also conducive for better reactivity of fly ash as compared to countries like Canada and US, where the cold climate is prevailing for most of the year.