Highway Research Record

II. PAVEMENT ENGINEERING AND PAVING MATERIALS
2. FLEXIBLE PAVEMENT
NEW PROJECTS
Laboratory Study to Determine the Compatibility of Drain Asphalt Modified Additives (DAMA)- An Additive in Porous Asphalt

Date of Start: August 2004 to February 2005
(i) Central Road Research Institute, New Delhi (R, I)
(ii) M/s Wooil Development Pvt. Ltd. (S)

Scope and Objectives
(i) To find out the compatibility of Drain Asphalt Modified Additive (DAMA) as an additive in porous asphalt mixes
(ii) Design of porous asphalt mixes
(iii) To find out the permeability properties of porous asphalt
(iv) To determine the performance of porous asphalt mixes using DAMA as an additive

Methodology

(i) Selection of gradation of aggregates for Porous Asphalt design
(ii) Design of Porous Asphalt by varying the DAMA content
(iii) Optimization of DAMA additive in Porous Asphalt mixtures
(iv) Testing for Permeability of the mix
(v) Performance tests like Permanent Deformation and Tensile Strength Ratio (TSR)

Conclusions

(i) Japanese specifications for grading of porous asphalt mixes with 60/70 paving grade bitumen and 1% DAMA as an additive      can be used in India, for better performance of porous asphalt mixes.
(ii) DAMA of 1 % by weight of mix results in a durable porous asphalt mix with 60/70 paving grade bitumen. The Cantabro      Abrasion loss was 17%, which is less than the Specified limit of 20%.
(iii) By adding DAMA as an additive at the rate of 1% by weight of mix, the air voids in the mix was maintained at 20%, which      was within the specified limit of 18 to 22%.
(iv) Optimum binder content for porous asphalt mix, as per the grading requirements of Japanese Specifications, was 4.6 % by       weight of aggregates (4.4% by weight of mix) fulfilling the minimum criteria of 4% by weight of mix.
(v) Permeability was 52.3 x10-2 cm/sec at 1% DAMA and 4.6% bitumen. The value obtained indicated that porous asphalt mix      can quickly drain off surface water even during heavy rains.

Significance/ Utilisation potential

The results obtained can be used for drafting tentative technical specifications of Porous Asphalt Mixes in India.

Limitations
Trial sections using Porous Asphalt Mixes designed under this study, need to be laid and monitored for their performance in order to evolve and formulate technical specifications for Porous asphalt mixes for Indian conditions using aggregates and bitumen, available in India.

Reports/ Publications

A technical report on the study has been submitted to the sponsor.