Mumbai Pune Express Highway

Repair of Bridge decks of Bumbai-Pune express highway using ACCMARG Technology of ACC-LTD.


The Mumbai-Pune Express highway is the first modern expressway in the country. The ministry of surface transport during the seven five year plan identified this corridor as amongst the three most congested national highway corridors and proposed it to be developed as part of national expressway system.

The 100 kilometer long stretch that winds up the hill and literally flies over the twin hill station resorts of Lonavala and khandala 600 m up in the western ghats. It continues its impressive routes into the inland plateau towards Pune The views while travelling up the western ghats looking towards mumbai are quite spectacular. The number of civil engineering structures on this express way are

 Underpass 26
 Overpass 20
 Major bridges/viaducts :6
 Minor bridges :21
 Box/slab culverts :81
 Cart tracks/pedestrian crossing :33
 Railway bridges :2
 Interchanges :4

It is indeed a pleasure ride to reach Pune in two hours from Mumbai using the express way. Such a marvel piece of work in the history of Indian road was not with out few blemices.
The 75 mm thick reinforced concrete wearing course over bridge decks was cracking. The cracking was may be due to many reasons. There were many articles in news paper stating the reasons of cracking. The problem of cracking was more severe at bridge decks at Khandala,kune and kusgaon.These threee bridge decks of roughly 60,000 square meter were cracking and there were potholes on the decks even before one year of opening the traffic.

The MSRDC the main body responsible for building the Mumbai-Pune express highway approached ACC to give solution to this severe problem. The ACC at that time has developed ACCMARG technology which can exclusively used for resurfacing of damaged concrete and bituminous roads.The same was used to solve the problem.

ACCMARG TECHNOLOGY

ACCMARG technology can be described as a semi flexible surfacing process consisting of open graded asphalt concrete filled with a special cement grout. The joint less wearing surface is approximately 30 to 100 mm thick applied to an existing asphalt or concrete pavement. The primary use of ACCMARG on road surfaces to provide protection against fuel spillage and resistant to abrasion and rutting. ACCMARG has been applied to various types of pavements in India. These includes bridge decks, road intersections. roads sections etc. The material has been tested in and around Mumbai on several high trafficed roads. Based on the experience to date ACCMARG pavement can withstand abrasive action from heavy vehicles, heavy point loads and pavement deterioration from fuel spills.

MATERIALS AND CONSTRUCTION

The open graded bituminous macadam mixture is similar to a porous bituminous course and is placed using standard paving techniques. The mix design procedure is used to determine the optimum bitumine content. The aggregate gradation is part of the ACCMARG technology. With a bitumine content of about 4% and rolling the surface with a predetermined number of passes produces a surface with 25-30% voids. The air voids content is critical since the grout canot penetrate the mix if sufficient voids are not present.
After laying the porous bituminous mix it is allowed to cool only then is the grout introduced into the voids.The grout is composed of a proprietary material of ACC which is wet mixed and poured onto the open graded bituminous surface.The excess grout is squeezed out by brooming the surface.

PROCEDURE OF CONSTRUCTION.

The ACC’S expert team visited L&T site at Lonawalla on 25 th December 2002.The three bridge decks at Khandala, Kune and Kusgaon were damaged and around 60000 sq meter area covering all the three bridge decks were to be repaired using ACCMARG technology

The badly cracked concrete panels were removed and fresh concrete panels were laid. The rest of the panels with surface cracks and before damaging further were used as such for ACCMARG placement.

.M/S Lonawalla construction limited which is local party who has supplied the aggregates to L&T for their concrete making has been finalized for bituminous macadam placement. The general requirement of mixing and placing the open graded macadam includes requirements of aggregates, bituminous binder, hot mix asphalt plant, surface preparation, spreading and compacting of porous bitumen macadam. The asphalt mixture is of two component mixture as given in Table-1
Table-1:Asphalt mix proportion.

Material Proportion
Bituminous material 3.7-4.3%
Aggregate 95.8-96.2%

M/S Lonawalla construction has used bituminous of 60/70 grade as per penetration test from BPCL. The aggregates used were from Chakan area 30km away from Lonawalla .The aggregates used are of following specifications.


Test VALUE
Water absorption 1.6%
Aggregate impact value 24.75%
Aggregate abrasion value 29.8%


There was a challenge to ACC team to execute ACCMARG laying job in two months time without stopping the vehicular traffic. The job started from the right carriage way of Kune bridge which is 430 meters long and 11 meters wide. Out of two lanes of right carriage way one lane was kept open for traffic and the other was used for ACCMARG laying. Fourty eight hours were required for ACCMARG placement with curing period of 36hrs.

The concrete surface is cleaned and emulsified bitumen Hincol is used as tack coat and 30 mm hot bituminous macadam is placed using paver.The mixing,spreading and finishing should be a continuous operation.Not more that two hours should be elapse between porous asphalt is mixed and the time of completion of rolling.During tack coating and the paving work only traffic necessary for the execution of the paving work was allowed on asphalt base course pavement. The paved bituminous macadam is rolled with 10 ton steel wheel roller to obtained 25-30% voids. The thickness of bituminous macadam and necessary camber is monitored at regular interval.

Mixing and pouring of grout.

The M-60 grout was made using ACCMARG dry powder and water at ready mix concrete plant of L&T situated at Kusgaon few kilometers away from the site. The grout was brought to the site in transit mixers. Grout mixing, pouring and spreading was a continuous operation. Not more than three hour should elapse between water is added to the mix and the time of completion..The ACCMARG pavement is cured for further 32 hrs and open to traffic. After completion of write carriage way left carriage way was completed by similar fashion.

ACCMARG laying at Khandala which is 670 meter long and 11 meter wide amd Kusgaon which is 1090 meter long and 15 meter wide were completed. The entire job is copleted by second week of march.In case of Kune and khandala decks the ACCMARG 30mm thick is laid expansion joint to expansion joint with taper near the joints.In case of kusgaon deck the expansion joints were raised by 30 mm by welding the circular metal bar to the existing expansion joints and then 30 mm ACCMARG is laid throughout.

The job was completed in time and handed over to client L&T. This experience has proved ACCMARG as unique wearing course material for bridgedecks .