Studies on Stone Matrix Asphalt with Warm Mix Technology using Sasobit and Zychotherm as Additives

The Stone Matrix Asphalt (SMA) mix is developed in Germany in the mid-1960s. It is a gap graded asphalt mixture which is intended to withstand deformity (rutting) resistance and durability by using the structural premise of stone-on-stone contact. Also, it is characterized by high coarse aggregates and fine particles, high binder content and fibre additives as stabilizers. It has low air voids with good drainage surface. Studies have been carried out on the SMA mixes under HMA conditions, in this study an attempt has been made to study the behaviour of SMA mix under warm mix conditions. The present work focuses on assessing the properties of Stone Matrix Asphalt Mix and also the effect of warm mix additives with addition of fibres. The objectives of the study are to obtain a desired gradation as per specification given by IRC SP 79 2008 by using locally available aggregates and other materials and to determine the optimum binder content for warm mix additives and optimum fibre content. To determine the above said properties the varying percentages of binder content from 5.8 %, 6 %, 6.2 %, 6.4 % and 6.6 %, fibre content 0.30 %, 0.35 %, 0.40 % and 0.45 % by total weight of aggregates and the varying percentages of warm mix additives i. e. Sasobit from 1 %, 2 % and 3 %, Zychotherm from 0.05 %, 0.1 % and 0.15 % have been considered for the research work. In this study, PMB-40 grade is used as the binder and hydrated lime is used as filler and Arbocel as fibre. After confirming that SMA warm mix with fibre showed better results than conventional SMA mix, At 2 % addition of sasobit and 0.35 % of fibre. Series of other tests are conducted on this mix to evaluate the engineering properties, the tests are - Draindown test, Indirect tensile strength test and Rutting test. The above tests results shown that the SMA warm mix with fibre showed better performance than conventional SMA mix.