Ravindra Gettu

Ravindra Gettu
Indian Institute of Technology Madras | IIT Madras · Department of Civil Engineering

About

251
Publications
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4,111
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Additional affiliations
December 2004 - present
Indian Institute of Technology Madras
Position
  • Professor

Publications

Publications (251)
Article
Full-text available
The production and use of concrete are responsible for natural resource consumption and adverse environmental effects. Evaluating sustainability aspects of concrete could help the industry identify processes with higher impacts, and work on them to perform in a holistic manner. This paper explores the environmental impact of concrete, with the eval...
Article
Supplementary cementitious materials (SCMs) can be used in concrete to enhance sustainability and reduce the concrete industry's carbon footprint. However, some negative perceptions about their long-term carbonation resistance are obstacles for large-scale implementation of such concretes. This study evaluated the carbonation resistance of 34 concr...
Article
In order to move towards a circular economy, it is relevant to maximize the usage of waste materials in construction activities. One such resource that could be extracted from abundant waste are Recycled Concrete Aggregates (RCA). Many methods have been proposed in the last few decades to improve the quality of RCA, with limitations in terms of ene...
Article
Full-text available
This paper aims to adjust the model parameters of the B4 and B4s models using newly collected laboratory data for blended cement concrete systems of strength grades 25 MPa and 65 MPa. Based on the data, regression analysis for the B4s model has been performed to capture the shrinkage response at later ages better. Also, suitable adjustment of the m...
Article
Full-text available
Use of supplementary cementitious materials (SCMs) has substantially increased in the construction industry in recent years. Long-term data on the effect of different SCMs on shrinkage and creep are scarce. Also, the appropriate prediction of shrinkage is important to ensure that the design can address the structural requirements when blended concr...
Article
Full-text available
The three mechanisms governing the strand-concrete (S-C) bond in pretensioned concrete (PTC) systems are: (i) adhesion, (ii) mechanical interlock, and (iii) friction. These mechanisms can be influenced by various parameters like the compressive strength of concrete (fc), applied prestress (fps), and embedment length of the strand (le). The existing...
Article
Full-text available
The characterization of the complete uniaxial compressive stress-strain curve of concrete is crucial for a more rational and reliable design of concrete structures. However, without intrinsic knowledge of the influence of different experimental control variables and the failure mechanisms of concrete, it is impossible to obtain a stable softening r...
Article
Full-text available
This paper explores the sustainability aspects of binders used in concrete 3D concrete printing. Firstly, a prospective approach to conduct sustainability assessment based on the life cycle of 3D printed structures is presented, which also highlights the importance of considering the functional requirements of the mixes used for 3D printing. The po...
Article
Textile reinforced concrete (TRC) is a promising material for strengthening of reinforced concrete beams due to the possibility of customizing both textile and matrix to achieve the targeted strain hardening under tensile load. Considering the complexity involved in material behaviour of TRC, the independent material characteristics majorly influen...
Conference Paper
In the past decade, increasing attention has been given to paving the roads with concrete mixtures due to their numerous advantages over bituminous roads. Further benefits could be expected by incorporating demolition waste recycled concrete aggregates (DRCA) in concrete pavements. Since DRCA generally exhibits inferior characteristics compared to...
Conference Paper
Portland cement manufacturing contributes to around 5-8% of the anthropogenic CO2 emissions globally. Consumption of portland cement in India and other emerging economies is expected to increase due to the steady growth of housing and infrastructure sectors. Finding alternatives to Portland cement is a global issue in recent times. To that end, cal...
Chapter
This chapter collects the description of the main creep testing procedures in fibre-reinforced concrete (FRC) as well as the equipment used by each participant laboratory in the round-robin test (RRT). The description of each procedure was directly provided by the participants and follows the same structure for each participant where institution id...
Article
In order to provide corrosion protection of tendons in post-tensioned (PT) concrete systems, the congested interstitial spaces between the strands and duct are ideally to be filled with cementitious grouts. However, many currently used grouts do not have the desired fluidity and resistance to segregation – leading to formation of voids, frothy grou...
Article
Full-text available
Fly ash and limestone calcined clay cement (LC3) are being used/introduced in concrete to enhance chloride resistance. In this study, sixty specimens (with steel in three concrete systems, namely OPC, fly ash, and LC3 with surface resistivity of ≈10, ≈25, and ≈200 kΩ.cm, respectively) were subjected to impressed corrosion and the results were compa...
Chapter
Full-text available
The design of precast tunnel segment under service load condition is mostly based on the axial force and bending moment (P-M) interaction diagram. This diagram is usually derived using flexural or tensile parameters obtained from short-term testing procedure. Considering the fact that the tunnel segments are subjected to prolonged loading, the effe...
Article
The versatility of textile reinforced concrete (TRC) by appropriately choosing binder and textile for various product applications necessitates its thorough characterization for arriving at design parameters. Due to the availability of wide variety of textiles in the market, the information gathered about the mechanical characteristics of textiles,...
Article
Use of fibre reinforced concrete (FRC) for pavements is advocated since the higher crack resistance could lead to lower slab thickness and higher joint spacing. The post-cracking capacity of FRC allows pavements to be designed and analysed considering the response beyond the elastic regime. The current paper presents possible failure patterns in FR...
Conference Paper
When concrete construction is concerned, the most important way to ensure more sustainability is to provide for the desired durability so that material, energy and expenditure is limited for the repair and rehabilitation during the expected service life, in addition to avoiding difficulties caused to the users or inhabitants due to problems that ma...
Article
Full-text available
Steel fibre reinforced concrete (SFRC) is used in various structural applications such as slabs, pavements, hydraulic structures, tunnel linings etc., due to their ability to limit the initiation and propagation of cracks, thereby improving the tensile load-carrying capacity and toughness. Two important parameters affecting the mechanical performan...
Article
This paper reports the assessment of rheological characteristics of cementitious pastes prepared with Limestone - Calcined Clay Cement, in comparison with ordinary Portland cement and Portland - Fly Ash cement. The impact on workability retention in concrete is also assessed. Further, a comparison of the performance of different commercially availa...
Article
The consumption of cement in India and other emerging economies is expected to increase because of the continuing push towards development of housing and infrastructure. The increasing production of cement and utilization of concrete are bound to have a major impact on sustainability. The present work proposes a framework for sustainability assessm...
Patent
Full-text available
The fracture characteristics of any type of concrete can be determined using a suitable analytical model combined with inverse analysis. The inverse analysis procedure generally consists of iterative modus operandi, which fit experimental flexural test data to obtain the parameters that define the tensile stress-crack opening (σ-w) curves. The prob...
Article
Full-text available
An experimental study on the behaviour of fibre reinforced concrete under flexure is presented, where pre-cracked notched beams were tested under cyclic loading for concrete with different dosages of hooked-ended steel fibres. The fatigue crack growth and stiffness degradation during the cycles are discussed in term of the rate of evolution of crac...
Article
Full-text available
About a decade of research carried out at IIT Madras on cementitious systems has shown that the partial replacement of portland cement with supplementary cementitious materials (SCMs) has benefits as well as limitations. The SCMs do not adversely affect the long-term compressive strength and drying shrinkage of concretes, though there may be some c...
Article
Full-text available
This paper presents a summary of the major findings from the studies conducted at IIT Madras on Limestone Calcined Clay Cement (LC3), in comparison with plain portland cement and fly ash-based binder. The study attempts to delineate the chemical and physical effects of binder components in LC3 on hydration and hardening, property development, binde...
Book
Full-text available
Abstracts of all the papers of this edition: https://icjonline.com/editionabstract_detail/022020 Website link: http://www.icjonline.com. It is with great pleasure that we bring you this special issue of the Indian Concrete Journal, a publication that has disseminated scientific work and new developments in the construction sector, and enabled tec...
Conference Paper
Full-text available
In the light of the increasing demand for cement in construction and dwindling reserves of cement-grade limestone, the blend of ground limestone and lower grade calcined clay has emerged as a potential candidate for large volume cement replacement. Studies of such ternary blended systems in paste and concrete reveal very interesting physical and ch...
Article
Full-text available
The article [Title], written by [AuthorNames], was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 3 December 2018 without open access.
Article
Full-text available
Cement is one of the most widely used materials in construction. This study presents a process-wise evaluation of energy use and CO2 emissions for clinker, Ordinary Portland Cement (OPC) and Portland Pozzolana Cement (PPC) using the principles of life-cycle assessment. Two cement plants located in India are considered as typical case studies. The g...
Conference Paper
Life cycle assessment (LCA) has been conducted to obtain the potential reduction in the environmental impact due to the production of limestone calcined clay cement (LC3), with respect to ordinary portland cement (OPC) and fly ash based portland pozzolana cement (PPC). A case study of a typical cement cement plant in South India is considered. It i...
Article
Full-text available
The effect of crack rate on the tensile stress–crack width relation of fibre reinforced concrete is studied experimentally, using the three-point bending test, where the post-peak flexural response of the material is determined over a range of loading rates covering 5 orders of magnitude. The tetralinear stress–crack opening (σ–w) relations are sub...
Article
This paper describes a unique international inter-laboratory study on the carbonation resistance of concrete prepared with different supplementary cementing materials. Concrete specimens – from 45 different concrete mixtures – prepared centrally in Lafarge Centre de Recherche (France)were shipped in a sealed condition to 4 other academia research l...
Article
Full-text available
Carbonation induced corrosion of the embedded steel reinforcement is a major deterioration mechanism of reinforced concrete structures, mainly in inland/ highway environments of tropical countries. Carbonation leads to uniform reduction in the cross sectional area of steel reinforcement. In general, Supplementary Cementitious Materials (SCMs) can i...
Article
This paper presents data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concretes (four M35 and three M50) with OPC, OPC+PFA (pulverized fuel ash) and limestone-calcined clay cement (LC3). Using these, the service lives of a typical bridge pier and girder with the PFA and LC3 concr...
Article
Full-text available
This paper presents the evolution of compressive strength and the modulus of elasticity of concretes with binary and ternary blends of ordinary Portland cement, fly ash and ground granulated blast-furnace slag (GGBS or slag). The study involved 54 concrete mixes with water–binder ratio (w/b) varying from 0.50 to 0.65 and the total binder content va...
Conference Paper
Full-text available
Various properties of limestone calcined clay cement (LC3) as a binder and those of concretes made with LC3 were assessed during the last four years at IIT Madras to understand its potential as an alternative mainstream cement. LC3 from two major industry-scale productions was used in the evaluation, and the major findings from the research are sum...
Article
This paper discusses the comparison of the flexural toughness parameters of fibre reinforced concrete (FRC) obtained from unnotched and notched beam tests. Results obtained from tests on a 40 MPa strength concrete reinforced with different dosages of hooked-ended steel, polypropylene and glass fibres have been used to correlate toughness parameters...
Article
The consumption of cement in India and other emerging economies is expected to increase because of the continuing push towards development of housing and infrastructure. The increasing production of cement and utilization of concrete are bound to have a major impact on sustainability. The present work proposes a framework for sustainability assessm...
Chapter
Strengthening of concrete structures through external bonding of fibre-reinforced polymer (FRP) composites has become a popular technique due to its advantages such as strength-to-weight and stiffness ratios, etc. In this investigation, a test method similar to RILEM TC-RC5 (used to evaluate the bond strength of rebars in concrete) is extended to e...
Chapter
The significant benefit of using fibre-reinforced concrete (FRC) is its improved energy absorption capacity, termed as toughness, and the consequent enhanced post-cracking load carrying capacity, which have resulted in applications such as tunnel linings, pavements, industrial floors, etc. There is limited knowledge regarding notched beam testing i...
Conference Paper
One of the most promising applications of FRC is the construction of pile supported slabs in order to address the issues of differential settlement, cracking, or long-term serviceability problems due to soil structure interactions. As previous studies have shown the advantage of using a hybrid combination of amorphous metallic fibres (AMF) and hook...
Article
A framework is proposed, along with two objective indices, for the selection of concrete mixture proportions based on sustainability criteria. The indices combine energy demand and long-term strength as energy intensity, and carbon emissions and durability parameters as A-indices, which represent the apathy toward these essential features of sustai...
Conference Paper
Grouted, post-tensioned (PT) systems are widely used in long-span segmental bridges, high rise buildings, nuclear vaults, silos etc. To achieve the corrosion-free target service life of 100+ years, the interstitial spaces between the strands and ducts of these PT systems are supposed to be filled with cementitious grouts. However, the use of poor q...
Conference Paper
Performance specifications for the cementitious grouts used in post-tensioning applications
Conference Paper
Full-text available
Limestone calcined clay cement (LC3) holds a promising potential to be an alternative low clinker cement in the place of plain portland cement. Over four years of on-going research in India, several properties of LC3 binder and concrete were assessed to understand the potential of LC3 as a mainstream cement. LC3 produced from two major industry-sca...
Conference Paper
Environmental impact due to the emission of carbon dioxide during concrete production can be taken care by reducing the clinker content in the cement. The clinker content can be reduced by replacing it with fly ash and limestone calcined clay. Such systems can have a potential to exhibit enhanced durability/service life when exposed to chloride and...
Article
In textile reinforced concrete (TRC), the yarns of the textiles are inherently wavy due to the manufacturing process. In most structural applications, this leads to delayed activation of textiles during loading and affects the composite performance negatively. In this context, the paper reports on the significance of mechanically prestressing or st...
Conference Paper
The mixture proportioning of concrete for sustainability should consider four aspects, without sacrificing affordability: the lowering of the carbon dioxide emissions; the minimization of raw materials required; reduction of energy demand during manufacturing and construction; and the longevity of the structure or other applications. Taking a set o...
Article
Full-text available
The adoption of any binder system for structural concrete depends on the performance characteristics desired for addressing the long-term deformation and durability concerns. The major properties influencing the performance includes the shrinkage characteristics governing the long-term deformation, and durability characteristics related to various...
Article
Full-text available
The fracture response of brittle materials like concrete can be characterised using modified linear elastic fracture mechanics models, such as the rising resistance curve (R-curve). In this study, the R-curve, determined by utilising the experimental response in the notched beam test with mode I fracture, is proposed as a measure of the toughness o...
Article
In recent years, there has been a rapid increase in the use of mineral admixtures for high performance and durable concrete. Plastic shrinkage cracking in such concretes is a serious concern in large surface area/volume applications. The present study has two objectives: firstly, to investigate the influence of incorporating fly ash and granulated...
Poster
Full-text available
The strand-concrete bond in (PTC) systems can be influenced by various factors like compressive strength of concrete (f’c) and prestress level (fps). The ASTM A 1081 proposed a pull-out test method to determine the bond strength of PTC systems. However, this specimen consists of an unstressed strand embedded in cement grout (instead of concrete); h...
Article
Full-text available
The fracture response of brittle materials like concrete can be characterised using modified linear elastic fracture mechanics models, such as the rising resistance curve (R-curve). In this study, the R-curve, determined by utilising the experimental response in the notched beam test with mode I fracture, is proposed as a measure of the toughness o...
Article
In the present work, the flexural behavior of concrete with different kinds of fibres have been characterized by center point loading (CPL) notched beam testing according to the EN 14651:2005 (E) and RILEM TC 162-TDF methods. The load-crack mouth opening (CMOD) and load-deflection curves were used to determine various toughness parameters, viz., fl...
Poster
Full-text available
This poster highlights the important parameters, which influences the environmental impact of different types of Cements in India.
Chapter
The significance of the creep behaviour of fibre reinforced concrete (FRC) in the cracked state is a matter of debate. As FRC in service could be in the cracked state, the serviceability and failure will depend on the stability of the cracks, and the alteration of the capacity to transfer stresses. Based on the present knowledge, this paper discuss...
Conference Paper
Considering that India is the second largest producer and consumer of cement in the world, it is understood that its production and use has a tremendous impact on the energy consumption and carbon dioxide emissions. More than 75% of cement in India is made by blending ground clinker with fly ash, ground granulated blast furnace slag, limestone or o...
Conference Paper
Full-text available
Concrete being alkaline is susceptible to attack by aggressive solutions. This is a huge problem especially in sewage treatment plants, where structures constructed with concrete come into contact with a variety of both organic (such as acetic acid) and inorganic (such as sulphuric acid) acids that are produced by bacteria. The present study attemp...
Conference Paper
The service life of reinforced concrete elements subjected to carbonation could be lesser than the design life due to premature corrosion initiation. The rate of carbonation in concrete systems with SCM is reported to be higher than that in concrete made of OPC at a similar mixture proportion. This article presents the service life estimation for c...
Conference Paper
Full-text available
This paper presents partial preliminary results of a comprehensive experimental programme to study the influence of fly ash and slag on the mechanical properties of common concretes, particularly those related to drying shrinkage. The measurements from specimens pertaining to 15 concrete mixes (with 15% mineral admixture dosage) indicate that the s...