Effects of Climatic Conditions and Temperature Gradient on Jointed Plain Concrete Pavement Slabs

A long lasting, reliable and economical transportation system is a critical component for the continuous movement of goods and services. Rigid pavements are widely used in construction world due to its high performance and serviceability. Traditional bituminous pavements and their needs for continuous maintenance and rehabilitation operations point towards the scope for cement concrete pavements. Cement concrete slab in a rigid pavement structure are exposed to different conditions at the surface in comparison to the bottom due to daily temperature fluctuations and results in the formation of temperature gradients in the slab. Transient gradients are due to the seasonal changes to which the slabs are subjected whereas permanent gradients are due to the slab condition during the setting of slab. The objective of this study is to determine the effect of temperature gradient and climatic conditions on a jointed plain concrete (JPC) pavement slab and to establish a proper temperature gradient chart which can be referred to depending on the climatic conditions existing in Kerala. A properly designed slab can reduce the formation of cracks and hence increase the life of slab. A detailed study in this area, can help in forming some codal provisions for the design of pavement slab depending upon the climatic conditions of Kerala. Keywords: Rigid Pavements, Bituminous pavements, Jointed Plain Concrete (JPC), Permanent gradients, Temperature Gradient

Improvement in bituminous surface course using waste plastic in acid-rain susceptible area’s

Acid rain as an important environmental issue has negative impact on bitumen performance, thereby shortening the service life of bituminous pavements. Rapid industrial and economic developments causes negative changes in the environment, including acid rain. Acid rain consisting of sulphuric acid and nitric acid has adverse effects on bituminous pavements. Both these acids react with the bitumen and adversely effect’s the properties of the bitumen leading to degradation of pavements at early stage of life. Early degradation of such pavements can be reduced to some extent by using waste plastic in bituminous surface course. Besides acid rain puts an adverse effect on the properties of bitumen, it also percolates deep down in the various down layers of pavements and reduces the serviceability of our pavements & its foundation. Waste plastic such as PET water bottles cannot only prevents the early degradation of pavements but also can prevents entry of acid rain into deep down layers of pavement as it absorbs acid rain water which makes it hydroscopic as because of it acid rain water does not percolate deep down into below pavement layers. In this paper, interaction between constituents of acid rain and bitumen is being investigated by analyzing the effect of sulphuric acid and nitric acid on control mix (mix without plastic content) & 6% WPET mix (mix with 6% waste plastic PET content) by using Marshal stability test. Also, it’s evaluated how improvement in bituminous surface course can be done by using waste plastic on acid rain area’s so that our pavements show good safety & serviceability.

A Comprehensive Study on Life Cycle Cost Examination for a Road (Preamser Hirnikheda Mundla) Project in Madhya Pradesh

A Life Cycle Cost Analysis (LCCA) is need to performed at the design period of the projects in order to be proficient to performed more profitable, to help take decision for type of pavement selection either flexible or rigid and also, to decide the comparative expense of different type of pavement. Specially for developing countries like India, due to insufficient funds for the project. However, now-a-days in India many infrastructure development projects like highways are being executed through loan from different external funding agencies like Asian Development Bank (ADB), World Bank, New Development Bank (NDB) etc. in case of a highway construction project, the major expenditure involves in construction of pavements. Therefore, before constructing a new road it is essential to check the life cycle cost analysis of different pavement options to select a most economical pavement option form techno-economic consideration. It is obvious that in our country most of the existing pavements are flexible pavement which has lower design life and higher maintenance requirements due to unpredictable traffic growth with heavy axel load as compared to the rigid pavements. Nowadays rainfall rate also generally found uncertain so at rainy seasons. So lots of case found that the highways are submersed during flood. These is the most common issue found in our developing country. For that bituminous pavements found damaged and cracked mostly. For that Rigid pavements are a good substitute on Flexible pavements, Rigid pavement have long life cycle (30 years as per IRC) with less maintenance cost, But the cost of construction of rigid pavement is higher than that of flexible pavement, but the Life Cycle Cost (LCC) including all maintenance are much less than of flexible pavements and its equally effective at submersible condition even in case of rehabilitation of existing bituminous pavements, concrete overlays or white topping can be good and beneficial alternative when compared to bituminous overlays. In the present study, an attempt is made to evaluate and compare the LCC of flexible and rigid pavements to be used for rehabilitation of an existing bituminous road. It provides results about the best suitable, economical and cost effective pavements. Net present value method of LCC is used for evaluating the pavements, this method takes into consideration initial construction cost and maintenance cost for design life period of both the pavements. With the help of this analysis a comparison of total life cycle cost of concrete pavements and bituminous pavements can be found out and best pavement alternative can be considered. Life cycle cost analysis: It is an important economic analysis used in the selection of alternatives that impact both initial and future cost. It evaluates the cost efficiency of alternatives based on the net present value (NPV) method which provides the total cost required during life cycle of the project. Keywords: Life Cycle Cost, Preamsar – Hirnikheda - Mundla Road, Rigid Pavement, Flexible Pavement, Traffic, Cost Estimates, MPRDC, Major District Roads.

Evaluation of rheological performance of a local modified bitumen by Styrene Butadiene Styrene polymer used in wearing course

In road construction, bitumen is the binder that gathered the different aggregates of road pavements. Bitumen, as a viscoelastic material, influences considerably the rheological behavior of bitumen concrete. The bitumen used in Algeria, showed its limits face to the traffic, which is increasing continuously. This research aims to valorize SBS polymer in wearing course by modifying a pure 35/50 bitumen. The present paper aims to study the polymer derived from styrene and butadiene (SBS) from the company Kraton Polymers International Ltd in the modification of a bitumen to improve its mechanical characteristics.To this end, the incorporation of SBS polymer was carried out according to two contents: 5.0 and 7.5% (by weight of asphalt), the objective being to evaluate the influence of this type of polymer on the rheological properties of the bitumen ordinary road including viscosity and modulus.The results reveal that the bitumen modified with 7.5% of SBS has better mechanical performance on the rigidity and the elasticity compared to the conventional bitumen. Recommendations have been made to implement a bitumen modification system to improve its quality and therefore the durability of bituminous pavements in the south of Algeria.

USING STEADY SHEAR RATE SWEEP PROTOCOL TO DETERMINE ZERO SHEAR VISCOSITY OF UNAGED AND AGED UNMODIFIED BITUMINOUS BINDERS

Rutting is one of the most significant distresses occurring in bituminous pavements at higher pavement temperatures. Researchers have been focusing on developing bitumen binder parameters that can be used to predict the rutting resistance of bituminous mixtures and Zero Shear Viscosity (ZSV) has proven its efficacy as a binder rutting parameter. A stepwise steady shear rate sweep test with two cycles of forward and backward sweeps was conducted at very low shear rates to determine the ZSV of unaged, short-term aged, and long-term aged unmodified bitumen binders. A convergence of the steady-state viscosities was observed at different shear rates in the first forward sweep. The response of the binders was independent of shear rate, time and the effect of shear history was negligible. As the shear rates correspond to the ZSV regime, ZSV was determined from the first forward sweep. The ZSV correlated well with the three existing rutting parameters.

A PROBABILISTIC APPROACH TO IDENTIFY THE REPRESENTATIVE RUT CURVE FOR A BITUMINOUS MIXTURE SPECIMEN USED IN A DRY WHEEL TRACKING TEST

Rutting is considered as a highly significant failure in bituminous pavements. Wheel tracking tests are widely used laboratory simulation tests to characterize the rutting resistance of bituminous mixtures. Considerable variation is observed in the accumulated rut depth at different locations along the wheel traverse and the representative rut curve obtained from different methodologies also shows significant variations. A probabilistic approach was adopted to analyze this scatter in the rut depth at a specific number of wheel passes and reliability based rut curves were developed. Weibull and lognormal distributions are better at characterizing the scatter in the accumulated rut depths at various locations than the normal distribution. The results from the probabilistic rut data for two different binders and two different bituminous mixtures tested at six different temperatures at specific number of wheel passes showed that different representative rut curves have different percentages of reliability. This work provides a rationale for choosing a representative rut curve from different methodologies.