ADVANCEMENT IN CONCRETE PAVING TECHNOLOGY

International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 ADVANCEMENT IN CONCRETE PAVING TECHNOLOGY Abhishek Rana1, Jayeshkumar Pitroda2, J.J.Bhavsar3 First Year Student, ME C E & M., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 1 Assistant professor, Civil Engineering Dept., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 2 Associate professor, Civil Engineering Dept., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 3 Abstract: Concrete pavements have been used for many years. However the recent advancements in the concrete paving technology have lead to better transportation facility. Here we shall discuss the history of concrete pavements and how it evolved from time to time. There is a disadvantage of concrete pavements, which is a high initial cost. However the concrete pavement proves to be more durable in the long run. Concrete pavements are generally used in almost all the developed countries, including some of the developing countries. Hence it is very important to find ways and techniques so that we can do concrete paving more effectively and efficiently. Research has been conducted and new technology and equipments have been developed which satisfies that need. New modern techniques which are currently being used have been discussed. Keywords: Concrete Paving Technology, Equipment, History, Modern Techniques. INTRODUCTION “Concrete paving technology means laying of concrete, effectively and efficiently, I. over a flat surface in order to make it smooth and convenient to use.” Usually rigid types of pavements are used for the construction of highways and other such roadways. Pavements are the critical elements of an efficient highway transportation system for moving people and goods. Without well-performing pavements, the transportation infrastructure cannot effectively function, road users suffer (in terms of increased costs, travel/commute time, and unsafe roads) and the overall economy suffers (in terms of higher costs for goods and commodities). Modern societies cannot function without mobility, and mobility requires well-performing pavements: it is as simple as that. Therefore, long-lasting pavements which are safer, smoother, and environmentally sensitive and can be costeffectively constructed and maintained are an important part of the transportation system. Crores of rupees are spent every year to construct, maintain, preserve, and rehabilitate the Nation’s highway pavement infrastructure. The accumulated investment in our roadway pavements is in the trillions of dollars. This investment needs to be protected and managed 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 176 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 efficiently so that generations of our citizens can continue to enjoy the benefits of one of the best roadway systems. The main objectives of concrete pavement engineering are: 1. Provide adequate serviceability at minimum cost. 2. Provide best serviceability possible with the funds available. 3. Maximum mobility at minimum cost. The materials and equipments used for the concrete paving are cement, aggregates, chemicals admixtures and pavers. Portland cement concrete (PCC) pavement, or rigid pavement as it is sometimes called, refers to the rigid concrete layer of the pavement structure that is in direct contact with the traffic. Typical concrete is composed of coarse aggregate (crushed stone and gravel), fine aggregate such as sand, Portland cement and then Portland cement, or through the use of admixtures, which are materials that are added to the mixture to enhance the properties of the fresh or hardened concrete. Once the concrete has been mixed, it is placed on a prepared base coarse and consolidated and shaped, typically using a slip-form paving equipment. PCC pavements are subject to challenging environments and loads over their lifetimes, so the concrete must be strong and durable, yet cost effective and workable. Coal fly ash (CFA) is often used in concrete pavements to improve the strength and durability of the pavement while reducing construction costs. Class C fly ash has been used as a substitute for cement in the concrete, and Class F fly ash, while not cementitious, acts as a pozzolan to enhance the long term strength and durability of concrete. In addition, CFA increases the workability of the concrete and usually reduces the water demand. The resulting concrete typically has a higher ultimate strength, and is more dense, providing resistance to infiltration from deicers. CFA also provides protection against alkali-silica reaction, a chemical reaction with reactive aggregate that can significantly reduce the working lifetime of the pavement. Blast furnace slag (BFS) has a number of different uses in concrete pavements. Air cooled BFS and palletized BFS have been used as coarse aggregate in concrete pavements and structures. Palletized BFS and granulated BFS can also be ground into a powder to make slag cement, which can be mixed with Portland cement as supplementary material and used to make concrete. Steel slag is also used to make slag cement for concrete, but its use as an aggregate is limited due to the expansion potential of the slag. Foundry sands are essentially high quality natural sands, and have successfully been 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 177 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 used as fine aggregate, while foundry slags, like other slags, can be used as coarse aggregate. Another aggregate source is actually old Portland cement concrete, which can be used as coarse or fine aggregate after crushing and processing. However, there are a few major challenges which have to be faced by the engineers. They are: 1. Constrained agency budgets. 2. Optimizing various design features that address local needs related to material availability, environment, site conditions, and future traffic. 3. Urban area traffic volumes and restrictions on construction zones. 4. Pavement noise considerations. 5. User demands for a safer and smoother ride. 6. Sound understanding of factors that affect concrete pavement behavior. 7. Developing durable concrete mixtures. 8. Environmental effects on short-term and long-term performance. 9. Sustainability considerations. II. HISTORY A brief view of how pavement design, construction and performance has evolved should help provide perspective on present and, possible, future practice. This short view into the past will start with the Romans, then moved on to the Macadam and Telford era, then into the first 150 years of asphalt and Portland cement concrete pavement. The evolution of pavement design will emphasize the U.S.A. and the U.K. and a bit more than for other parts of the world. A. Roman Roads In fairness, the Carthaginians are generally credited with being the first to construct and maintain a road system. The Romans eventually decided that their neighbors across the Mediterranean were a bit of a threat to the empire destroying Carthage (The Carthage ruins are located in Tunisia (Northern Africa) next door to Algeria (on the left) and Libya (on the right — so to speak).) It is suggested that the Romans took up the practice of a military road system from the Carthaginians. It is estimated that the Romans built about 87,000 km of roads within their empire (about equal to the length of the U.S. Interstate system). 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 178 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 Apparently, there is no record of “traditional” roads in the U.K. prior to the Romans . For the most part, the main Roman roads in the U.K. (total of about 4100 km) were for military purposes in that they connected camps which were about 30 km apart (or about one day’s march). Since the primary purpose of these roads was for foot soldiers, the roads were straight, but virtually without regard to grade. They generated high noise levels, were rough and labor intensive (slave and “statue” labor often used). The Roman design for their primary U.K. roads generally consisted of four layers (top to bottom) as follows: Summa Crusta (surfacing): Smooth, polygonal blocks bedded in underlying layer. Nucleus: A kind of base layer composed of gravel and sand with lime cement. Rudus: The third layer was composed of rubble masonry and smaller stones also set in lime mortar. Statumen: Two or three courses of flat stones set in lime mortar. The total thickness was as much as 0.9 m and road widths of 4.3 m or less. An illustration of the Roman pavement structure near Radstock, England, is shown as Figure 1. Roman roads in some countries have been up to 2.4 m thick. These structures had crowned (sloped) surfaces to enhance drainage and often incorporated ditches and/or underground drains. As one might expect, Roman road building was varied to suit local conditions and materials — not unlike today actually. Road design and construction languished for about 1,200 years thereafter. Figure 1 Cross sectional view of Ancient Roman Road Sourcehttp://www.pavementinteractive.org/article/pavementhistory Figure 2. Ancient Roman road. http://www.crystalinks.com/romeroads.html 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 179 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 Roman road construction was not inexpensive. Updated construction estimates of the Appian Way in Italy are about Rs.124,000,000 per km. The oldest known road in the U.K. is near the River Brue in southwestern England. Actually, the “road” is a 6,000 year old walkway which was discovered in 1970 in a peat bog. The construction of the road coincides with the arrival of the first farmers in the U.K. about 4,000 B.C. B. Telford Thomas Telford served his apprenticeship as a building mason. Because of this, he extended his masonry knowledge to bridge building. During lean times, he carved gravestones and other ornamental work (about 1780). Eventually, Telford became the “Surveyor of Public Works” for the county of Salop, thus turning his attention more to roads. Telford attempted, where possible, to build roads on relatively flat grades (no more than 1 in 30) in order to reduce the number of horses needed to haul cargo. Further, the pavement section was about 350 to 450 mm in depth and generally specified in three layers. The bottom layer was comprised of large stones (100 mm) wide and 75 to 180 mm in depth) . Figure 3 shows cross section of telford. Figure 3 Cross section of Telford. Source http://www.pavementinteractive.org/article/pavement-history/ It is this specific layer which makes the Telford design unique [Baker, 1903]. On top of this were placed two layers of stones of 65 mm maximum size (about 150 to 250 mm total thickness) followed by a wearing course of gravel about 40 mm thick (refer to Figure 2). It was estimated that this system would support a load corresponding to 88 N/mm (500 lb per in. of width). 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 180 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 C. Macadam John Macadam (born 1756) observed that most of the “paved” U.K. roads in early 1800s were composed of rounded gravel [Smiles, 1904]. He knew that angular aggregate over a well-compacted subgrade would perform substantially better. He used a sloped subgrade surface to improve drainage (unlike Telford who used a flat subgrade surface) on which he placed angular aggregate (hand-broken, maximum size 75 mm) in two layers for a total depth of about 200 mm [Gillette, 1906]. On top of this, the wearing course was placed (about 50 mm thick with a maximum aggregate size of 25 mm) [Collins, 1936]. Macadam’s reason for the 25 mm maximum aggregate size was to provide a “smooth” ride for wagon wheels. Thus, the total depth of a typical Macadam pavement was about 250 mm (refer to Figure 3). An interesting quote attributed to Macadam about allowable maximum aggregate sizes was that “no stone larger than will enter a man’s mouth should go into a road” [Gillette, 1906]. The largest permissible load for this type of design was estimated to be 158 N/mm (900 lb per in. width). Figure 4 shows cross section of macadam. Figure 4 Cross section of Macadam Source http://www.pavementinteractive.org/article/pavement-history/ In 1815, Macadam was appointed “surveyor-general” of the Bristol roads and was now able to use his design on numerous projects. It proved successful enough that the term “macadamized” became a term for this type of pavement design and construction. The term “macadam” is also used to indicate “broken stone” pavement. By 1850, about 2,200 km of 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 181 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 macadam type pavements were in use in the urban areas of the UK. Macadam realized that the layers of broken stone would eventually become “bound” together with fines generated by traffic. With the introduction of the rock crusher, large mounds of stone dust and screenings were generated. This resulted in the use of such fines resulting in the more traditional dense graded base materials which in turn produced pavement thicknesses as thin as 100 to 150 mm. The first macadam pavement in the U.S. was constructed in Maryland in 1823. III. TECHNIQUES 1. Laser screed technology: It is now available in India which could be used for smaller industrial projects, commercial work and residential slab-on grade. It is a ride on a machine that establishes grade by laser, disperses concrete by anger, vibrates and consolidates the concrete. The console mounted computer maintains grade with laser precision and monitors the screed elevation at a rate of 5 times per second. The 8 foot wide screed head is mounted on a 12 foot telescopic boom, making it possible to accurately laser screed 100 square feet of concrete with each pass. The benefits offered by this technology include floors of unequaled flatness and levelness, reduced labor costs because of fester placing and reduced formwork. Due to laser and computer technology one can be assured of greater accuracy and precision for increased productivity. Figure 5 shows Laser screed machine. Figure 5 Laser screed machine 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 182 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 2. Slip-form paving: There are two methods of paving with concrete: slip-form and fixed form h sip-form paving, a machine rides over the area to be paved-similar to a train moving on a set of tracks. Fresh concrete is deposited in front of the paving machine which then spreads, shapes, consolidates; screeds end float finishes the concrete in one continuous Operation. This operation requires close coordination between the concrete placement and the forward speed of the paver. The two lift paving systems being available today loads the second layer of concrete by a specially designed transfer system added to the front of the paver that places the material into a unique hopper located under the layer. A special paving system provides proper vibration and consolidation to the individual layers to give the surface a smooth finish. Patented mould incorporates two-layer paving into a single mould design. This system eliminates the use of more equipment for the job and eliminates having to extend the paver to great lengths between the front and back legs for second layer paving. This system has the ability to change the depth of the top layer without modifications to the machine with an adjustable leading strike-off. The single mould design features leading vibrators, spreading auger and an adjustable strike-off for the first layer of concrete. The second layer features a hopper design to be charged with a conveyor auger system, a spreading auger and a unique tamper bar for consolidation before the second strike off. The two-lift system allows the incorporation of the In-The-Pan Dowel Bar Insertion System. Figure 6 shows the slip form paving equipment. Figure 6 Slip form pavement equipment 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 183 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 3. Vacuum dewatering concrete flooring : Concrete in the conventional way but with a higher slump so that the workability is good and concrete pouring and spreading is done fast. Filter pad is placed on the fresh concrete leaving about 4 inches of fresh concrete exposed on all sides. The top cover is placed on the filter pad and rolled out till it covers the strips of the exposed concrete on all sides. The top cover is then connected with the vacuum pump through a suction hose and pump is started. Vacuum is immediately created between filter pads and top cover. Atmospheric pressure compresses the concrete and the surplus water is squeezed out. This process lowers the water content in the concrete by 15-25%. The dewatering operation takes approx 1.5-2 minutes per centimeter thickness of the floor. Figure 7 Vacuum dewatering processes 4. Roller compacted concrete (RCC): RCC, a durable paving material that carries heavy loads, is now developing as a fast, economical construction material for darns, off-highway pavement projects, heavy-duty parking and storage areas, and as a base for conventional concrete pavement. RCC is a stiff, zero-slump concrete mixture with the consistency of damp gravel comprised of local aggregates or crushed recycled concrete, Portland cement, and water. The mixture is placed and roller compacted with the same commonly available equipment used for asphalt pavement construction. The process requires no forms, finishing, surface texturing, or joint 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 184 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 sawing and sealing. RCC has low water content, requiring it to be mixed in a continuous flow system, usually a site batch plant or pug mill, instead of a ready mixed truck. A dump truck transports freshly mixed RCC to the construction site where workers place the mixture in layers, called lifts, using a conventional asphalt spreader. Lifts, which range from 20-30 cm in thickness, are then compacted using a vibratory steel wheel and pneumatic tire rollers, immediately after workers complete compaction; water is applied as a fine mist to cure the concrete. Because of Its low water-cement ratio, RCC typically has high strengths similar to, or even greater than, conventional concrete. RCC's high strength properties combined with ease of construction and high rate of production often make RCC more economical than a flexible pavement. RCC provides all-weather access for trucks and heavy equipment supplies a firm base and allows the facility to control drainage. Even though RCC is not a smooth pavement, a layer of asphalt may be used to cover the surface and smoothen out the roadway. As regards dam construction using RCC, typically, contractors produce a no-slump concrete mix and spread it in 300 mm. Layers from abutment to abutment atop a rock foundation that stretches across the waterway to be dammed. Because the RCC mix is too dry to be effectively combined in ready mix trucks, the concrete is usually mixed at a temporary plant erected near the dam site and transported by conveyer belt, front-end loader, or dump truck to the placement site. The newly placed layer of RCC, called a lift, is compacted with a vibratory roller. Continuous placement of RCC is normally specified on dam projects to minimize cold joints between the horizontal concrete layers that could inhibit bonding of the concrete layers to each other. Figure 8 shows roller used for compacting. Figure 8 Roller used for compacting 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 185 International Conference on: “Engineering: Issues, opportunities and Challenges for Development” ISBN: 978-81-929339-1-7 IV. CONCLUSION  Thus, from all the gathered facts and studies, it can be concluded that concrete pavement have proved to be beneficiary to human kind. The transportation system has become more rapid and more convenient due to concrete pavements. Moreover the concrete pavements can be constructed quickly and conveniently. Although they might have a high initial cost, it proves to be more convenient in the long run.  Since its inception, the concrete paving techniques have evolved. Man now make pavements with more ease and accuracy than ever before. All credit goes to the advancements in research of concrete paving technology. And in the future with the arrival of automation, we can see more improvements in the concrete paving technology. ACKNOWLEDGMENT The Authors thankfully acknowledge Dr. C. L. Patel, Chairman, Charutar Vidya Mandal, V. Er.V.M.Patel, Hon. Jt. Secretary, Charutar Vidya Mandal, Dr. F. S. Umrigar, Principal, BVM Engineering College, Dr. L. B. Zala, Professor and Head, Civil Engineering Department, BVM Engineering College, Prof. J. J. Bhavsar, Associate Professor and P.G. Coordinator (Construction Engineering and Management), B.V.M. Engineering College, Mr. Yatinbhai Desai, Jay Maharaj construction, Vallabh Vidyanagar, Gujarat, India for their motivations, infrastructural support and cooperation to carry out this research. REFERENCES [1] Glenn A. Shephard, 'Laser Technologies Application To Construction' A Report Presented to the Graduate [2] [3] [4] [5] [6] [7] Committee of the Department Civil Engineering in Partial Fulfillment of the Requirements for the Degree of Master of Civil Engineering, University of Florida, Summer 1999 Ravindra K Dhir, Peter C. Hewlett “Concrete in the Service of Mankind: Radical concrete technology, Volume 4” E & FN SPON Publication. Transportation Research Board of National Academics http://www.crystalinks.com/romeroads.html http://www.constructionequipment.com/concrete-pavers http://www.cptechcenter.org/ http://www.pavementinteractive.org/article/pavement-history 11th April, 2015, S.N. Patel Institute of Technology & Research Centre, Umrakh, Bardoli 186