Analytical Investigation for Determining Ressilient Modulus for Interface Layer of Aggregates
Quality road aggregates have become rare and costly in many places in India due to massive construction activities required for the development of new infrastructure facilities. The pavement industry seeks ways of improving lower quality materials that are readily available for use in roadway construction. Cement treatment has become an accepted method for increasing the strength and durability of soils and marginal aggregates. However, cement-stabilized bases can also be the source of shrinkage cracks in the stabilized base layer, which can reflect through the asphalt surface. Introducing “Interface Layer of Aggregates (ILA)” between stabilized base and bituminous concrete (BC) layer appears to be very favorable. The present paper presents the determination of resilient modulus of ILA using FPAVE software. Figures have been developed to determine resilient modulus, varying the CBR value, the thickness of cement treated base and the thickness of interface layer of aggregates which is useful to determine the pavement thickness for cement treated base.
Analysis of Flexible Pavements using IIT Pave
: The traffic pattern has changed since then and so has the technology. The volume of tandem, tridem and multi-axle vehicles has increased manifold and heavier axle loads are common. Since pavements are constructed as per the standards and specifications of design, which may not serve for the design period efficiently, safely, and economically due to early deterioration of materials with different properties. Due to environmental concerns as well as legal restrictions on quarrying, the focus has shifted from large scale use of conventional aggregates to use of local, recycled and engineered marginal aggregates in construction. It is generally known that failure of asphalt pavement is due to fatigue cracking and rutting deformation, caused by excessive horizontal tensile strain at the bottom of the bituminous layer and vertical compressive strain on top of the subgrade.  This presented study aim at expanding the scope of pavement design by including alternate materials like cementitious and reclaimed asphalt materials, and subjecting them to analysis using the software IITPAVE. In this study a road stretch is selected around Bangalore and engineering properties of subgrade soil has been studied. The different pavement composition materials like Cementitious Base and Cementitious Sub-base of aggregate interlayer for crack relief. Cementitious base and sub-base with SAMI at the interface of base and the bituminous layer.Foamed bitumen/bitumen emulsion treated RAP or fresh aggregates Cementitious sub-base has been designed, analyzed and compared with the conventional granular base and granular sub base. The use of different composition materials in pavement structure improves serviceability based in comparison with conventional granular base and granular sub-base. Among all the composition the cemented base and sub base with SAMI gives better serviceability because of substantial reduction in strains, thickness and cost effective compared to other design. Hence it can be recommended for stretch selected for studies.
Mechanical behaviour and durability of high volume fly ash cementitious composites
The purpose of this research is to separate different morphological particles of ASTM class F fly ash, and study their effect on mechanical behaviour and durability of high volume cementitious mixtures. In this research wet separation of raw fly ash is carried out, which resulted in three layers of different morphological particles. The first layer of particles float, comprise of about 1-5% of fly ash, is identified as cenospheres or hollow spheres. The second layer of particles is measured to be 55-60% of raw fly ash and consisting of porous spherical and rounded particles rich in Si and Al. The third layer particles is measured to be about 35-40% of raw fly ash. High volume fly ash cementitious composites containing second or third layer particles are tested under compression and bending, highlighting a higher strength and ductility in comparison to cementitious ones containing raw fly ash particles. KEYWORDS. Cementitious matrix; Raw fly ash; Second layer particles; Third layer particles.