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.
COLD IN-PLACE RECYCLING ON LOW-VOLUME ROADS IN AUSTRIA
Modern methods for road maintenance should involve used construction materials, take account of environmental compatibility, and eliminate road damage economically and durably. Regarding these basic requirements, attention should be paid to cold in-place recycling of damaged asphalt layers using cement stabilization. Within the last few years, cold in-place recycling has become an appropriate alternative for the rehabilitation of low-volume roads in Austria. In the course of documentation carried out at the Institute for Traffic and Transportation Engineering of the Vienna University of Bodenkultur, the individual steps of construction were analyzed. The advantage of the described procedure is that none of the old pavement need be hauled to a special repository. An innovative method for cold in-place recycling on low-volume roads using cement stabilization is described. The first step of this method contains a detailed analysis of the section to be restored, including bearing capacity measurements and the determination of the grading curves of existing unbound layers. Grading curves are also determined for the existing asphalt layer after trial milling in order to consider refinement by milling. This analysis forms the basis for adding material before milling in order to achieve a well-graded aggregate. On the construction site, the necessary additional aggregate is spread over the existing pavement. In the next step, the cement binder is distributed on the road surface. A soil stabilizer breaks up the existing road structure and mixes it thoroughly with the aggregates and binder that were distributed beforehand. The leveling and compaction are done with a grader and a vibratory roller. An after-treatment with a vibratory roller is carried out up to 3 days later to create microcracks and prevent the appearance of open stress-caused cracks at greater intervals. The paper also describes in detail the analysis of existing pavement before milling, including bearing capacity measurements. Existing results and statements describing achievable quality level are given. Results showing increased and homogenous bearing capacity conditions after milling and cement stabilization are shown. Concluding remarks also show that this way of reconstruction is an economic means of conserving raw materials and protecting the environment.