Utilization of Reclaimed Asphalt Pavement Material in Wet Mix Macadam (W.M.M)

Reclaimed asphalt pavement (RAP) is one of the innovative and effective technologies in many places in the world. The utilization of RAP is rapidly increasing popularity and becoming an emerging technique in India. As per IRC-120:2015, removing or reprocessing pavement materials containing aggregates that are bitumen coated is termed as RAP. These materials are gained through a process in which the existing surface pavement is reclaimed and reused after processing for reconstruction, resurfacing, or repaving. Well graded and high-quality aggregate are achieved from this process. Proper utilization of RAP with specified properties and specified percentages, not only serve as an alternative useful pavement material but also helps in reducing the usage of natural construction material, that will directly reduce the overall cost of projects. By conducting tests as per MoRTH specifications (5th Revision), the various characteristics of RAP material and fresh aggregates are observed. The main objective of the study is to carry out the performance tests: Modified Proctor test on fresh material as well as on material mixed with reclaimed asphalt pavement i.e. 10%, 20%, and 30% of total mix and to achieve optimum moisture content and maximum dry density by using Modified Proctor Test. Attempts are carried out to design a new pavement using Indian Road Congress (I.R.C-37:2018) guidelines and utilization of RAP material. Economic benefits are calculated in terms of fresh and RAP (10%, 20%, and 30%) mix material pavement.


1.
Introduction In India, road network plays an important role in the increase in the rapid growth of the economy, industry trade, and tourism. All remote places are connected via a road network for caring out various economic activities. A Road network also integrates people from different places and cultures. By linking various facilities like airports, ports and railway stations, road network plays an important role in transport infrastructural development. A study on India roads indicates that excessive pollution growth and development in road construction have resulted in extensive usage of bituminous material and aggregates in the last 55-67 years. In our country, most of the roads are flexible pavement using and these roads have a disadvantage that it requires a periodic maintenance action due to heavy traffic loads and environmental conditions. (Mishra.B:2015). As  2 that is of thousands of kilometers, we are consuming a large amount of non-renewable energy and materials from Mother Nature. Recycling, a logical and practically possible is one of the best ideas to control the never-ending demand for fresh construction material. By consuming recycled materials we also cut down a large number of construction costs. Near about 67% of Indian highway, roads were mainly constructed with Hot Mix Asphalt (HMA). As the years pass these infrastructure ages, so roads and highways require maintenance. The material can be reused to repair, reconstruct, and to maintain the original highway.These materials are gained through a process in which the existing surface pavement materials are reclaimed and reused after processing for reconstruction, resurfacing or repaving are known as Reclaimed Asphalt Material. RAP is a valuable material used in HMA to decrease or cop up the demand of fresh materials. RAP material controls the usage of fresh aggregate and fresh bitumen in pavement construction. In 1973, RAP was used for the first time, however, the usage percentage was low as during that time there was a lack of knowledge that how it will affect the pavement characteristics. Nowadays near about higher percentages i.e. 20% RAP is being utilized to reduce construction costs and fresh material and reuse of demolished old asphalt pavements. Mainly RAP designed pavements are used for rural road construction but with new technologies and proper knowledge, we can construct in urban areas also.

2.
Laboratory Investigations To check materials that are to be used is suitable in bituminous mixes, it is necessary to carry out the physical tests on materials. In the present research different materials used are RAP aggregate and natural aggregate. The purpose of this research is to examine the performance between natural aggregate and various RAP aggregate mixtures that is 10%, 20%, and 30% of Wet Mix Macadam obtained from standardized laboratory tests. The procedure includes Modified Proctor Test parameters that are Maximum Dry Density and Optimum Moisture Content mixes using RAP materials.
• RAP Material Properties RAP sample was obtained from the stockpile at RKC infra built, Vasad. The obtained RAP material was milled by the milling operation done on Vasad-Tarapur state highway in Anand district of Gujarat state, India. The milling process is shown in Figure 1 done on Vasad-Tarapur state highway road and Figure 2 shows the RAP material stockpiled at RKC hot mix plant.    Table-3 a graph representing the Job mix for WMM fresh mix is shown in Figure: 3.

B. Job Mix Formula for WMM using Fresh material + RAP material
We performed a Mix design with and without RAP mixture i.e. 0%, 10%, 20%, and 30%, of WMM grade-II. Blending of RAP material and fresh material was prepared i.e. 10% of RAP materials + 90% fresh materials. Table-4 shows the combined gradation of RAP and fresh aggregates meeting the requirement as per MORTH 5 th revision specification. Respective blend graphs were plotted and shown in Figure: 3. After the extraction of binders, the aggregates were recovered and kept for oven drying for 24 hours. After oven drying the gradation of recovered aggregate was performed, shown in Figure:3, and from the figure, we can conclude that gradation of RAP aggregates fall below the lower limit of WMM (Grading-II) as per table 400-13 which is shown in Table 4.

A. Modified Proctor Test
The parameters of the Modified Proctor Test for WMM fresh mix and mix containing different percentages of RAP material i.e. 10%, 20%, and 30% are carried out, as per MoRTH specifications (5 th Revision). Parameters of the mix like maximum dry density and optimum moisture content are observed for various test % of RAP mixes shown in Table 5.

A. Pavement Design
A stretch of 1 KM length is selected for pavement design and the various design traffic parameters are shown in Table 6. Using the below Equation described in IRC: 37-2018 guidelines, we could calculate a million standard axel (MSA).

5.
Conclusion [1] Usage of RAP material up to 30% shows the overall saving of 2.44 million Rs in total flexible pavement construction cost. [2] Based on the pavement design, material quantity of the WMM layer for 1-kilometer length was found to be 3000 m 3 . By replacing with RAP material, it was found saving in quantity from 300.00 m 3 to 900.0 m 3 respectively.