STC

Dronacharya Group of Institutions Greater Noida conducted two weeks workshop on “Construction of Flexible Pavements” under the National Mission on Education though ICT (NMEICT) in collaboration with NITTTR from 9th May - 13th May 2016. 15 faculty members from DGI - Greater Noida attended the STC.

The objective of the STC was to provide a general overview of the equipment and procedures involved in the construction of flexible pavements.

Day 1: 9th May, 2016

The event was inaugurated by Dr. Ajay K Duggal, Associate Professor, Civil Engineering, NITTTR, Chandigarh. Dr. Duggal began the session with sharing the objectives of the STC. He gave a brief overview of the course and asked the participants to attend all the sessions punctually.

Dr. Duggal started the session with a presentation on “Types of Highways”. He explained roadway construction: carriageway, pavement, kerb, shoulder and sidewalks. He discussed the major types of pavements: flexible, rigid and composite. He said that Flexible pavements support loads through bearing rather than flexural action. They comprise several layers of carefully selected materials designed to gradually distribute loads from the pavement surface to the layers underneath. The design ensures the load transmitted to each successive layer does not exceed the layer’s load-bearing capacity.

In the next session Dr. Duggal explained the three types of bituminous: (1) Bitumen laid, aggregate on top (2) Aggregate laid, bitumen on top (3) Pre-Mix. He then discussed Bituminous Construction at site. There was a discussion on Sub-Grade: Natural Sub - grade and Compacted Sub-grade. He discussed the desirable properties: stability, incompressibility, permanency of strength, good drainage, ease of compaction and minimum changes in volume and stability under adverse conditions of weather and ground water.

Day 2: 10th May, 2016

Dr. Duggal initiated the session with a presentation on “Bituminous Materials”. He discussed road networks in India. He stated that most of the roads are flexible pavements. Flexible pavements are preferred over cement concrete roads as they have a great advantage that these can be strengthened and improved in stages with growth of traffic.

Day 3: 11th May, 2016

Dr. Ajay K Duggal discussed the PMC (Pre Mix Carpet) construction features. He discussed the process of applying the PMC: (1) Apply tack coat (2) Prepare the mix in the hot mix plant (3) spread the mix uniformly (4) compact the surface (5) apply seal coat immediately after laying the carpet. He then discussed Close Graded Premix Surfacing (also called Modified Mix Carpet), which is an improvement over PMC. Aggregate premixed with bituminous binder. He described the construction features of MMC. He further explained deal coat which is a surface treatment used for sealing the voids in the bituminous surface. He discussed how hot mix is transported. He talked about the process of spreading seal coat.

Day 4: 12th May, 2016

Dr. Ajay K Duggal initiated the session with a presentation on “Stabilization of Sub - grade”. He discussed the importance of subgrade stabilization. Often poor subgrade soils do not possess the strength to support road construction activities and the subsequent intended traffic loads. Subgrade separation and stabilization geosynthetic materials maximize load distribution and increase the effective bearing capacity of the subgrade to help provide a stable foundation layer from which a permanent or temporary road / working platform can be built. He discussed the objectives of stabilization. He stated that stabilization provides an alternate method to improve the structural support of the foundation for many of the subgrade conditions.

Day 5: 13th May, 2016

The session started with a presentation on “Warm Mix Asphalt and Half Warm Mix Asphalt” by Dr. Sangita. She stated several process have been developed to improve the mixtures. She discussed zeolites, which releases water molecules when mixed with liquid asphalt at the plant. Zeolite is added 0.3% by mass to the mix. She explained wax modifier, an organic additive, a paraffin wax which reduces the viscosity of the binder at mixing and compaction temperatures.

Dr. Sangita concluded her presentation with a question and answer session. Mr Gyanendra Kumar, Assistant Professor, Civil Engineering, Dronacharya Group of Institutions (Greater Noida) raised a query regarding the difference between Asphalt, Bitumen and Emulsion.

Dr. Duggal discussed the issues related to the materials and activities involved during the construction of flexible pavements. He talked about foam mixed recycling of reclaimed bituminous materials. He discussed repaving that is a process of recycling the materials. Softer material costs less to recycle as it needs less heat to attain its workable temperature.

The participants gave their suggestions and feedback of the workshop. The session concluded with vote of thanks from Dr. Duggal.

Some Glimpses: