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The physical properties and performance of hot mix asphalt are governed by the properties of the aggregate, properties of the asphalt binder and asphalt–aggregate interactions. The study is aimed to compare the behaviour of bitumen containing various type of modifiers [styrene-butadiene-styrene (SBS) and ethylene-vinyl-acetate (EVA)] and aggregates (acidic and basic characters) for preparing hot mix asphalt on permanent deformation. Rutting and static creep tests were performed on various mixes to evaluate permanent deformation. Dynamic shear rheometer was used to determine the rheological properties and hence rutting parameter (G*/Sinδ). The results indicate that polymer modification increased rutting resistance. Moreover, samples prepared with EVA are more resistant to deformation compared to those prepared with SBS. Mixes consisting of quartzite aggregate are likely to deform more compared to marble mixes, both for modified and unmodified bituminous mixes, but the recovery of quartzite mixes on removal of load is also more.

This work presents the laboratory study conducted on fly ash and rice husk ash as soil stabilizers. Using these stabilizers, the deformation behaviors of subgrade soil-mixtures under repeated triaxial loading was conducted. Resilient strain, permanent strain and resilient modulus were ascertained at different deviator stress level and confining pressures at constant moisture content. Admixing of fly ash and rice husk ash reduces the maximum dry density but increase the water demands. The variations of elastic deformation and resilient modulus were significantly influenced by fly ash and rice husk ash contents. Better performances were observed for admixed soil irrespective of number of load applications. The results obtained from the laboratory confirm the potential use of subgrade soil admixed with fly ash and rice husk ash with respect to the permanent deformation.

The present study aims to stabilise local clayey soil with a varying percentage of rice husk ash (RHA). The RHA was collected from rice milling located near Roorkee city. As this material is abundantly available in the local area, efforts have been made to investigate the potential of the RHA–soil mixtures with respect to shrinkage limits, compaction characteristics, unconfined compressive strength (UCS), triaxial test, split tensile strength test and the California bearing ratio (CBR) after subjected to different humidity conditions, so as to utilise in road construction, if found suitable. The laboratory results indicate that admixing of RHA decrease the maximum dry density, but increased optimum moisture content with increase in RHA content. Inclusion of RHA not only improved CBR, UCS and split tensile strength of clayey soil but also, shown considerable improvement on cohesion and angle of internal friction too.

The main objective of the present investigation is to assess the usefulness of agricultural and industrial waste as a soil admixture, and focused to improve the engineering properties of soil to make it capable of lower layer of road construction. Present investigation describes the behavioral aspect of soils mixed with industrial waste materials viz. fly ash (FA), rice husk ash (RHA) & bagasse ash (BA) and agricultural waste material rice straw ash (RSA) to improve the load bearing capacity of the soil. Clayey soil has been considered using four different types of stabilizer viz. FA, BA, RHA & RSA ranging from 5 to 35% by weight of soil. The physical and chemical properties of these stabilizers were ascertained and compared. Admixing of all these stabilizers improve soaked CBR values substantially and dramatic reduction in dry density was observed.