Abstract: Transportation network plays a substantial role in the everyday life of social beings. The preservation of this vast infrastructure needs appropriate and cost-effective design techniques, which depends upon the selection and proportion of binder and aggregate. With the passage of time, as compared to HMA (Hot Mix Asphalt), WMA (Warm mix asphalt) has become extreme prevalent in the road construction industry, because WMA offers the opportunity of production asphalt mix at a reduced temperature than conventionally used for HMA, hence saving energy, cutting CO2 emission and improve environmental quality. This study aims to assess the impact of sasobit (an organic WMA additive) on permanent deformation and moisture susceptibility of asphalt mixes. Under the scope of this paper, the authors have added three percentages of sasobit that is 1%, 2% and 3% to check the effect of increasing sasobit percentage on rutting and moisture damage of asphalt mixes. In summary, rut depth of WMA as obtained from Hamburg Wheel Tracker Device (HWTD) slightly decreased from that of HMA, while rut depth at 1% and 2% was even less than that of 3% sasobit. A slight increase in moisture damage as compared to control mix was observed by adding sasobit, as illustrated by decreased Tensile Strength Ratios TSR.
Abstract: Large quantity of the quarry dust gets produced annually in the quarries during the extraction of the crushed coarse aggregate. As a result, disposal problems of this material gain significant momentum as these disturb environmental systems also. Now-a-days many of the countries like India is facing problems of ban on the extraction of sand and lacunae in procuring of fine aggregate, which is important constituent of the concrete. To overcome this problem, present study is focused on the suitability to utilize the quarry dust in Self Compacting Concrete (SCC) partially as fine aggregate with the natural fine aggregates. In this work, quarry dust is used as replacement of sand in a different level (0%, 15%, 30%, 45% and 60%) for producing the SCC. Fresh properties such as slump flow and V-funnel time have been measured for all mixes and hardened properties as compressive strength, splitting tensile strength and flexural strength of the concrete have been checked for all the mixes and it has been found that optimum utilization of quarry dust up to 30% can been done to produce SCC without compromising with its properties.
Abstract: The introduction of wide range of novel raw materials and composites are tuning exceptionally the construction industry on its head. The recent research trends majorly intensified on hybrid concept using the varied materials collectively. This study primarily aims at experimentally investigating the response of concrete exterior beam column joint with Hybrid Reinforcement Technique (HRT) for reverse cyclic load conditions. The on-site fabricated, Hand Layup Carbon Fibre Reinforced Polymer (CFRP-HL) stirrups and the conventional steel main reinforcements form a hybrid reinforcement system in this study. The on-site constructed CFRP-HL reinforcement serves as a substitute for pre-fabricated CFRP rebars which has limitations and inflexibility in adapting the construction alterations. In total six types of specimens, a couple of test specimens are strengthened with HRT and another with external bond CFRP fibre wrap. In the remaining three specimens, one with non-conventional steel detailing and a couple of conventional joints that are designed according to IS 456:2000 and IS 13920:1993 respectively. In addition, the influence of varied spacing of stirrups in specimens is studied separately. Further, the test results on overall strength, stiffness, load deflection characteristics, dissipated energy and ductility of test specimens is evaluated and discussed. The use of CFRP-HL with steel as hybrid combination enables to comprehend the benefit from their distinctive characteristics. This proposal strongly improves the greater flexibility of using CFRP-HL in field as needed.
Abstract: Roads are the most important component for the economic and social development of any country. India has a total road network of more than 6 million kilometers, which carry around 90% of passenger traffic and 65% of freight traffic. More than 20% land area of India is covered with soils having low California bearing ratio (CBR) and shear strength values. The pavement constructed over such soils will lead to rapid increase in construction and maintenance costs. This study presents a laboratory investigation about the combined effect of geotextile and geogrid reinforcement, placed in layers at various depths from top of specimen, on the strength behaviour of poor subgrade soil. Heavy compaction, soaked CBR and unconfined compressive strength (UCS) tests are conducted. The test results indicate significant improvement in CBR and UCS values for all geosynthetic reinforced cases, whereas ductility and rupture strength remains almost constant as compared to virgin soil. Scanning electron microscopy (SEM) analysis shows significant bonding between soil particles and fibers of geogrid, causing stress transfer from soil to reinforcing material and hence preventing soil from overstressing. It is concluded that combination of geogrid and geotextile can be used effectively for reinforcing poor subgrade soil.
Abstract: The integrity assessment of jacket platforms using non-linear pushover analysis in the past had shown that most of the platform failure occur due to the lack of strength in the pile foundation. When the failure of jacket platforms in extreme weather conditions were studied, it was observed that the foundation was intact while the platform failed. This disagreement between the simulation and the actual condition can be explained by the phenomenon of Aging of pile foundations. Experimentally, the axial capacity of pile foundations have been found to be improving with time due to aging. The rate of improvement of the capacity can be empirically predicted using the properties of the soil in which the pile is installed. An empirical equation namely Skov and Denver equation was utilised to determine the improvement in capacity of offshore jacket piles in this study. This improvement was incorporated into the pile-soil modelling of jacket platforms using a new, yet very simple technique of stepping up the axial soil structure interaction curves. Pushover analysis of two offshore jacket platforms with the modified pile-soil model was done using the software SACS. The RSR (Reserve Strength Ratio) obtained from the pushover analysis showed significant difference due to the incorporation of the axial aging effects of the piles. Jacket A has showed a maximum improvement in RSR of 11% and a maximum reduction of RSR of 11% whereas Jacket B has showed a maximum improvement in RSR of 27% and a maximum reduction of RSR of 17%. The study has given a good insight into the changes in behaviour of a jacket platform due to aging of its pile foundations and is expected to improve the structural integrity assessment techniques of aged offshore jacket platforms.
Abstract: Current seismic design practice assumes the base of the building to be fixed and does not consider the flexibility of foundation and soil. This assumption is realistic only when the structure is founded on solid rock or when the relative stiffness of the foundation soil compared to the superstructure is high. Whereas, in reality due to natural ability of soil to deform, supporting soil medium modifies the response of the structure during earthquake to some extent. In this work the effect of soil structure interaction on seismic response of building resting on different types of foundation was studied. Present work aims to study the effect of soil structure interaction on seismic response of building resting on fixed base, pile foundation, raft foundation and combined pile-raft foundation. G+9 RCC building is analyzed for earthquake loads considered in zone III by response spectrum method and storey displacement and base shear force of building by considering and without considering SSI effect is found out by using MIDAS GEN software.
Abstract: Fracture mechanical studies have become a vital aspect of the design of concrete structures. This work aims to analyse/validate the size-effect of structural components in light of principles of Linear Elastic Fracture Mechanics (LEFM). Various models of a quasi-brittle material with different geometries have been analysed for Stress Intensity Factors (SIF) using Abaqus/CAE: a finite element analysis software. The effect of crack-to-depth ratio, span-to-depth ratio and specimen size on SIF values have been studied. Also the variation in SIF values with respect to changing the position of concentrated load application and initial notch on the specimen have been studied. It is found that for a particular notch-to-depth ratio, the SIF increases with a decrease in specimen size. Also, at a constant span-to-depth ratio, SIF increases with increase in the notch-to-depth ratio.
Abstract: Increase in developmental activities and the limited availability of suitable sites for civil engineering project construction is greatly encouraging engineers to consider improvement of weak soil deposits for constructing infrastructures. Among various weak soil deposits, “Dredged Material” from famous Lakes is causing serious health and environmental problems. Dredging of lakes generate lot of waste material, which needs to be disposed-off methodically without disturbing environment. Many Researchers have reported that geotechnical properties of dredged material qualify it for use in the manufacture of high value advantageous products. For all applications, a brief study about Geotechnical characterization of dredged material is very important, which will help in proper use of this material as well as sustainable development of the Dal Lake. Therefore, in this study, an attempt is being made to highlight some geotechnical properties of this solid waste for its bulk utilization in various construction activities. The stabilization of the dredged soil with lime is an effective means of chemical stabilization of soils and it is seen that the index and engineering properties of dredged soil are significantly altered by the addition of lime. A significant step is being taken by this study to achieve economic use of construction materials by attempting to prevent the wastage of such soil material through the improvement of its properties to meet the requirements.
Abstract: Composite materials play a vital role in many industrial applications. Researchers are working on fabrication of new composite materials worldwide to enhance the applicability of these materials. The present study aimed to investigate the effect of Nano clay loading as filler on the mechanical properties of the bamboo fiber yarn reinforced polyester composite. Five different types of composite specimen were prepared with Nano clay loadings of 0 to 4 % weight fraction using hand lay-up technique. It was observed that the composite sheet with 1 wt % nano clay content exhibited the optimized tensile and flexural strength. However the mechanical properties tend to decrease with addition of nano clay content from 2 to 4 wt %. In spite of that the values of mechanical properties with 2 and 3 wt % nano clay content is higher than 0 wt % nano clay content.
Abstract: Performance-based seismic design (PBSD) is an approach, in which the design aim is to deliver a structure capable of meeting certain predictable performance objectives under different levels of earthquake motions. In order to ensure the desirable performance of buildings or structures, the structural parameters such as strength, stiffness and ductility or deformability should be reasonably proportioned. Conventional methods of seismic design have the objectives to provide life safety (strength and ductility) and damage control (serviceability drift limits). However, little information is available on how the building reacts to a seismic hazard. The basic concept of PBSD is to provide the engineers with the capability to design buildings that have a predictable and reliable performance in case of a seismic hazard. This procedure compares the capacity of a structure (in the form of a pushover curve), with the demand imposed by the earthquake on the structure (in the form of response spectra).The present paper determines the performance point of the structure, using Capacity Spectrum Method (CSM). A 7-storey building has been considered for this purpose and pushover analysis is carried out. An attempt has been made to perform the seismic analysis for the building, to obtain the performance point.