Question

write a report on the below topic given with following instruction

Topic: mechanical evaluation of asphalt mastics produced using waste stone sawdust.

get familiar with the design and/or construction of sustainable /eco-friendly flexible pavements and recognize the need and engage in the civil engineering life-long learning process.

Introduction.

Summary.

Objectives and history.

project details.

Impact of the sustainable/eco-friendly approach (advantages and disadvantages).

conclusion.

Answer 1

INTRODUCTION.

A mixture of asphalt with sand, asbestos, crushed rock, or similar material; used like cement. Also known as mastic asphalt.

SUMMARY: Mechanical Properties of Asphalt mastic/ Stone Mastic Asphalt(ASM), and Cost of inclusion are discussed.

OBJECTIVE: Mastic Asphalt is an ideal material for a whole range of construction applications, in both new build and refurbishment, where a smooth, seamless, durable surface is required. It offers total waterproofing integrity for roofing and tanking and acts as a tough working surface in flooring and paving.

HYSTORY:

A material that can boast a history dating back to the Phoenicians, the product was patented by Mr Claridge in Paris in 1837 and mastic asphalt became known as Claridge's Patent Asphalt

MECHANICAL PROPERTIES:

​​​​The rheological and failure properties of eight asphalt-filler mastics were characterized using new testing techniques being developed within the SHRP program for testing asphalt binders.

Physical hardening was observed to result in shifting the master rheological curves to longer loading times without affecting the shape of the master curves. The anticipated influence of mastic properties on the main distress types of asphalt pavements was considered. The influence of fillers on low-temperature cracking was hypothesized to be independent of filler type. Therefore, it is expected that the asphalt binder will control the cracking mechanism.

Based on the energy concept, the addition of the filler is expected to improve resistance to stress-controlled fatigue while for strain-controlled fatigue the improvement, if any, is expected to be minimal. Fillers are expected to significantly improve rutting resistance as a result of increasing moduli (viscous component). Effect on rutting is expected to be asphalt-filler-specific.

Life cycle cost:

Costs are always difficult to obtain and compare. Evidence to date in both the United States and Australia shows that the initial costs of SMA are 20-40% higher than conventional dense graded asphalt in place in road applications. To determine whether SMA is more cost effective than conventional dense graded asphalt surfacing, whole of life or annualized cash flow techniques are used. These techniques take into account the higher initial cost of SMA (20-40% higher than conventional dense graded asphalt in place in road applications) and the longer life expectancy of SMA.

The increased initial costs of SMA compared to conventional dense graded asphalt result from the use of premium quality materials like higher bitumen content, use of fibers, increased quality control requirements and lower production rates due to increased mixing times. However, costs vary considerably with the size of the project, and also on haul distances.

Reasons behind increased cost of SMA:-
a) The costs of SMA are on average 25% higher than dense graded asphalt,
b) The period between reheating is on average 10 years for dense graded
And 15 years for SMA,
c) Continued inflation rates at 4%
d) A 30 year analysis period.
However, even considering the potential for increased costs, the Georgia Department of Transport (DOT) have found the use of SMA to be quite cost effective based on improved performance and the potential for increased service life.

The Alaska DOT (NAPA, 1998), has found that the approximately 15% increase in SMA cost compared to conventional mixtures is more than offset by a 40% additional life from a reduction in rutting.

ADVANTAGES:
• High stability against permanent deformation (rutting) and high wear resistance.
• Slow aging and durability to premature cracking of the asphalt
• Longer service-life
• SMA has a higher macro-texture than dense-graded pavements for better friction
• Reduced spray, reduced hydroplaning and reduced noise.
• Good low temperature performance
• Even though SMA has a higher cost than conventional dense mixes, approximately 20 to 25 percent, the advantages of longer life (decreased rutting and increased durability).

DISADVANTAGES
• Increased cost associated with higher binder and filler contents, and fibre Additive,
• High filler content in SMA may result in reduced productivity. This may Be overcome by suitable plant modifications,
• Possible delays in opening to traffic as SMA mix should be cooled to 40 oC to prevent flushing of the binder surface, and
• Initial skid resistance may be low until the thick binder film is worn off the top of the surface by traffic.

4. CONCLUSION
Stone Mastic Asphalt has proved superior on heavily trafficked highways all over the world during recent years. The use of SMA is increasing in popularity amongst road authorities and the asphalt industry.