Environmental Sciences and Sustainable Engineering Centre (ESSENCE)

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The use of fibre reinforced concrete (FRC) for applications such as slabs-on-grade and pavements has been established to be advantageous due to the superior crack resistance properties, enhanced post cracking moment carrying capacity, and higher performance under fatigue, shrinkage and temperature stresses. In this context, the goal of this doctoral work is to develop and propose a comprehensive methodology for the design of fibre reinforced concrete pavements/slabs-on-grade incorporating the inelastic design techniques and material characteristics specific to FRC. The material parameter adopted in design is the equivalent flexural strength at a specified deflection. A database of flexural toughness parameters based on existing codes has been prepared for typical fibre concretes incorporating various fibres in different dosages and also used for comparison of material performance. The paper discusses the proposed design methodology based on yield line analysis, which results in an economical solution with fibre concretes in comparison to plain concrete. Emphasis has also been given to fatigue stress design in the case of pavements by incorporating a stress correction factor based on S-N relations of FRC. The need to determine the actual temperature differential in slabs has also been illustrated based on the results from experimental program performed at IIT Madras.

World University root node

Proceedings of the 10th fib International PhD Symposium in Civil Engineering

A design methodology for fibre reinforced concrete pavements and slabs-on-grade

Use of fibre-reinforced concrete for pavements, though widely established, lacks comprehensive standardization with respect to both design as well as implementation. Most widely used design methods have adopted the established techniques used for slab-on-grade, mostly due to lack of studies specific to pavements. This is a major drawback since the failure of slabs-on-grade is predominantly caused by static loading whereas the failure of pavements, more often than not, occurs at much lower stresses due to fatigue. In this context, a comprehensive design methodology exclusively for FRC pavements is proposed here including the effect of fatigue in conjunction with inelastic analysis. The static load design equation is based on Meyerhofs ultimate load (yield line) analysis. The material capacity is estimated using the flexural capacity factored by a stress reduction factor for FRC in the cracked and the uncracked state obtained from suitable S-N relations to account for the fatigue stresses. The material parameters incorporated in the design equations include the flexural strength and the equivalent flexural strength of FRC obtained using the unnotched prisms as per Japanese standards (JSCE-SF4).

American Concrete Institute, ACI Special Publication

A comprehensive methodology for the design of fibre-reinforced concrete pavements

Increased use of fibre reinforced concrete (FRC) in India has resulted in the urgent need to standardise testing and characterisation. The current paper addresses the different available techniques and gives pre-normative suggestions for toughness characterisation. The use of an unnotched beam test is advocated here considering the dearth of laboratories for performing more sophisticated tests and the use of FRC being by-and-large restricted to slabs-on-grade and other non-structural applications. In this study, different types of steel fibres were incorporated in a typical M35 concrete used in India in flooring applications. Flexural tests were conducted to obtain the load-deflection curves and determine various toughness parameters, viz., flexural strength, equivalent flexural strength, equivalent flexural strength ratio and residual strength. The load-deflection curves of FRC with undulated fibres differed significantly from those with straight hookedended fibres in that the concrete failure often occurred with significant crack branching and spalling. The tests indicate no significant change in compressive strength due to addition of fibres while the flexural strength of FRC is slightly higher than that of plain concrete emphasising the need for determining the flexural strength by testing rather than using values from empirical equations or from tests of plain concrete. Specifically, the results illustrate that hooked-ended fibres do not influence the behaviour until after the peak and are more efficient in improving toughness, especially at larger deflections resulting in higher equivalent flexural strengths, in comparison with the undulated fibres. As expected, the higher aspect ratio and higher dosage of steel fibres impart more toughness to the concrete. It is shown that different combinations of fibre type and dosage can yield similar equivalent flexural strength ratios (Re,n) and different fibres at same dosage can have different Re,n values. It was observed, in general, that the variability of flexural strength is much higher than that of the compressive strength and that the variation of results is lower for straight hooked-ended fibres. The scatter in the residual strengths is much higher than that in the equivalent flexural strength, which results in a relatively lower characteristic value for the former in comparison to the latter at similar deflections. Based on the study, recommendations have been made for consideration in an Indian test standard.

Indian Concrete Journal

Characterisation of the toughness of fibre reinforced concrete - Revisited in the Indian context

98th ESA Annual Convention

Reducing uncertainty through data-driven model development

Phosphorus (P) indices, originally developed to assess the risk of P export to aquatic systems from agricultural fields receiving inorganic fertilizers and livestock manures, are being used for other P sources with different characteristics and methods of application. This study determined Pennsylvania P index scores for eleven crop fields of Penn State University's Living Filter system receiving 130 kg P2O5 ha-1 (115 lb P2O5 ac-1) in 2008 via sprinkler irrigation of municipal wastewater effluent. A baseline assessment of P index treated effluent irrigation as surface application of completely soluble P source material with maximum potential of runoff P loss. Three fields located ≤22 m (200 ft) from streams ranked high and very high in P loss rating under baseline assessment. Modified assessments involved changing the application method multiplier and P source coefficient to more accurately reflect the year-round intermittent application of P via sprinkler irrigation. All fields were ranked as having low risk of P export using the modified parameters. Site monitoring data from nearly 50 years of effluent irrigation show no evidence of excess P transport to groundwater or off-site surface water, suggesting that baseline assessment might be overestimating P loss rating of some fields. Results underscore the need to tailor P indexing tools to address the differential risk of P loss for specific P sources and application methods. Copyright © 2013 Soil and Water Conservation Society.

Journal of Soil and Water Conservation

Applicability of phosphorus site indices to wastewater effluent-irrigated cropland

AGU Fall Meeting Abstracts 2012, B43F

Two-way Coupling of a Process-Based Crop Growth Model (BioCro) and a Biogeochemistry Model (DayCent) and its Application to an Energy Crop Site in the mid-west USA

AGU Fall Meeting Abstracts 2012, H51O

Impacts of energy cane expansion on ecosystem services: A Florida case study

A methodology for the design of steel fibre reinforced concrete (SFRC) pavements and slabs-on-grade is suggested incorporating the equivalent flexural strength to account for the residual moment carrying capacity. The design methodology is a modification of the yield line theory proposed by Concrete Society Report TR34 (2002). The methodology proposed has the advantage that it extends the familiar design methods of plain concrete slabs-on-grade design. Based on cost analysis, optimization of dosage of fibres and thickness has also been attempted to obtain economical solutions for typical loading.

8th RILEM International Symposium on Fibre Reinforced Concrete: Challenges and Opportunities (BEFIB2012)

On the Design of Steel Fibre Reinforced Concrete Pavements and Slabs-on-Grade

Irrigation reuse of municipal effluents conserves freshwater resources and avoids direct nutrient discharges to surface waters. The sustainability of agricultural reuse programs, however, may be challenged by evolving phosphorus (P)-based nutrient management policies. This paper assesses the agricultural and environmental implications of soil P accumulation from effluent irrigation and discusses sustainability under guidelines to control P export in agricultural runoff and drainage. For typical regulatory maximum irrigation rates (5.1-cm-wk-1), secondary effluents containing 3-4-mg-P-L-1 provide ∼90-kg-P-ha-1-yr-1 and cause soil P enrichment beyond levels needed for optimum crop yields. Applied P potentially falls short of crop needs for advanced wastewater treatment processes with low (<0.5-mg-L-1) effluent P or where hydraulic rates are restricted by soil, climatic, or regulatory conditions. Except for some locations where well-drained low P-retention soils overlie shallow groundwater, effluent-irrigated P has minimal impact on water quality. Most site assessment tools (P indices) were developed to identify fields with high P loss vulnerability from manure and commercial fertilizer application and do not explicitly address effluent-applied P. Adoption of P-management regulations not accounting for the differential behavior of P in effluent-irrigated fields may unnecessarily restrict agricultural irrigation of reclaimed water. © 2012 American Society of Civil Engineers.

Journal of Environmental Engineering (United States)

Phosphorus management for sustainable agricultural irrigation of reclaimed water

The current scenario of depleting resources has lead to a major thrust in developing and applying highly sustainable solutions to construction industry. Therefore, it has become essential to devise designs based on materials that cost the least for the transportation network and at the same time have a minimum environmental impact. Though there are a few modern material solutions that may meet these criteria, like the use of steel fibre reinforced concrete (SFRC) for pavement constructions, a proper evaluation of the performance and impact of utilization of such materials is lacking. Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) offer the means to evaluate the sustainability, and have been used in this paper to provide frameworks analysing Asphalt, Jointed Plain concrete (JPC) and Steel Fibre Reinforced Concrete pavements. In this work, asphalt, JPC and SFRC pavement sections have been designed as per the respective IRC guidelines so as to get equivalent designs for the given traffic loading, environmental and material conditions. Subsequently, LCCA is done as per the procedure provided in the Federal Highway Administration’s Interim Technical bulletin and LCA is done by using the process approach for each of the pavements. The assessment indicates where sustainable practices can be directed to so as to minimize environmental impacts in the initial stage of the pavement life cycle. The paper also discusses the limitations and difficulties of carrying out life cycle assessment and life cycle cost analysis for highways in India.&nbsp;