Most of the reputed suppliers today supply motor graders and dozers with an accurate grade system, where one can upload the design of the site and grading will be done automatically by machine to the required specification. This saves time, fuel, manpower and operating cost of the machine. Equipment India throws light on the importance of proper grading before compaction.
The government is encouraging private sector participation by working out public-private-partnership (PPP) deals in the road sector, in order to be able to meet the growing need of road development. To meet the demands of planned investments, the market will more than double between 2009 and 2014, with a noticeable increase in sales of all types of construction equipment used for road-making, according to Off-Highway Research reports. As per its data, the growth rate of motor graders from 31.52 per cent in 2009-10 would reach over a whopping 163 per cent by 2014. (The total volume of motor graders in 2009 was 342 units, which in 2010, became 450 units (a growth rate of 31.52 per cent) and the forecast is a growth in volume around 900 units by 2014, a growth rate of 163 per cent compared to base of 2009 figures.
Speaking about the importance of proper grading before compaction, Pradeep Kathuria, Head - Essar Equipment Bank, Essar Projects India says, “Grading in civil engineering and construction is the work of ensuring a level base, or one with a specified slope, for a construction work such as a foundation, the base course for a road or a railway, or landscape and garden improvements, or surface drainage. The earthworks created for such a purpose are often called the sub-grade or finished contouring.” Earlier, the effectiveness of grading was measured by surveying and measuring after grading. “This is a manual process and needs more manpower and man-hours,” Pradeep adds. “Most of the reputed suppliers today supply motor graders and dozers with an accurate grade system, where we can upload the design of the site and grading will be done automatically by machine to required specification. This saves time, fuel, manpower and operating cost of the machine.”
“In the early days, dozers were most commonly used for grading. But with the advent of motor graders of heavier capacity, the quality of surface finish and speed of construction improved dramatically. Therefore, the contracting fraternity has adopted it without much hesitation,” says Dr B Sivarama Sarma, Joint General Manager & Head R&D, L&T Construction Research & Testing Centre, L&T ECC Division. According to Sarma, “The grades and levels are controlled using motor grader only, without which maintaining camber is very difficult. The grading also ensures uniform spreading of heaps of earth being dumped by tippers; the motor grader ensures the compactor is effectively used with minimum load on it. The effectiveness of grading will be checked with reference to levels at various stages to ensure proper camber, etc.” Speaking about the factors affecting grading, Sarma says, “The effective grading depends on the skills of grader operator, size and quantity, and the alignment system of the blade. The availability of skilled grader operator is a cause of concern. However this problem can be mitigated by ensuring regular training of machine operators.” Sarma also gives some tips while selecting compactors and motor graders. “Scope of the work and project time schedule governs the choice of machines. It is also governed by the performance record of the machine, down town period, availability of spares and service support.
“In today's construction industry, grading plays a more important role than it ever has before. In reality, this phase of construction represents the very foundation of the construction industry. It is absolutely necessary to have a smooth and uniform surface to achieve uniform compaction density,” says Sunil Sapru, President, Liugong India.
According to Jitendra Sharma, Chief Executive Officer, Action Construction Equipment, “The market for compactors and motor graders are in the growing phase, and it would continue to be in the same trajectory for near foreseeable future barring a one or two-year aberration because of a change of guard at the Centre. The road-building equipment industry will see a CAGR of minimum 25 per cent year after year.”
Pankaj Dara, Associate Vice president - Construction, TIPL states, “Grading is the process of modification of the existing landform to accommodate new structures and to ensure positive drainage. Consideration must be given to utilities such as water, gas, power communication services and sewerage for disposal of wastewater and storm water. Grading process requires a careful change of contours. The land may be graded or adjusted to suit the architectural or engineering requirements to meet the variations in the ground level so that the original surface is disturbed the least.” Pankaj further elaborates, “Extensive alterations in the landform may lead to unstable conditions resulting in erosion, landslides, floods and complete destruction of eco-system. Knowledge of grading technology is therefore very important in the site planning process. It is needed to make a detailed levelling between building and landscape of any site. Site planning grading takes care of the adjustment necessary between fixed levels structures and use areas within the boundaries of a site. Grading is therefore one of the most important aspects of any new project.”
“Compaction without proper and accurate grading will produce an uneven surface. Construction activities require accurate and levelled compacted surface to provide super-elevation, drainage and landscaping, thereby making grader essential equipment,” says SM Roy, Chief Executive Officer, Lanco Infratech. Effectiveness of grading is determined with grader capacity to spread the fill material in designed thickness and slope within the specified tolerances, avoiding wobbly and jerky movement. The grader should complete the work within the specified time without much rework. Roy further adds, “Factors affecting grading are required rolling gradient or slope, lift thickness, fill material properties, environmental conditions, grader power and operator skill. We are planning to go in for few compactors and graders for an upcoming highway project.”
Speaking about the range offered by TIPL, Pankaj says, “Caterpillar offers graders in the 125-205 HP range in India for construction and mining applications, the most popular model being the 120K which is a 145 HP machine used mainly on construction projects. Incidentally, Caterpillar also is the market leader in India for motor graders with a market share of close to 40 per cent. Some of the unique features of the cat motor graders are load sensing hydraulics which comprises the advanced Proportional Priority Pressure Compensating (PPPC) electro-hydraulic valves to provide superior implement control and enhance machine performance in all applications, continuous matching of hydraulic flow and pressure to power demands creates less heat and reduces power consumption, leading to fuel savings.” He further adds, “Another unique feature is the Electronic Clutch Pressure Control (ECPC) which smoothes the gear shifts and improves inching control. The system uses inputs from the transmission and operator control to modulate the directional clutches and produce consistent shifting.”