Anagi M Balachandra - Academia.edu (original) (raw)

Papers by Anagi M Balachandra

Cement and Concrete Research, Jun 1, 2022

Anti-corrosion Methods and Materials, Jul 28, 2023

Purpose This study aims to report the development and experimental evaluation of three innovative... more Purpose This study aims to report the development and experimental evaluation of three innovative corrosion-resistant modified epoxy coatings, namely, nanocomposite/toughened, self-healing and hybrid epoxy coatings, for application on steel substrates. Design/methodology/approach The corrosion resistance of these coatings was evaluated in a highly corrosive environment of salt fog spray for 2,500 h of exposure. Electrochemical impedance spectroscopy (EIS) measurements in sustained exposure to NaCl in a saturated Ca(OH)2 solution, rust creepage measurements at the location of scribe formed in the coatings and adhesion strength test were used to assess the performance of the innovative coatings. Commercially available marine-grade protective epoxy coatings were used as the reference coatings. Findings The test results showed that the modified epoxy coatings exhibited excellent corrosion resistance when exposed to an aggressive environment for extended periods. The EIS measurements, rust creepage measurements, pull-off strength and visual appearance of the aged modified–epoxy–coated specimens confirmed the enhanced corrosion resistance of the modified epoxy coatings. Originality/value Among the three types of modified coatings, the hybrid epoxy coating stands out to be the best performer.

Abstract : Versatile classes of indigenous inorganic binders and reinforcement systems were devel... more Abstract : Versatile classes of indigenous inorganic binders and reinforcement systems were developed and characterized using resources that are abundantly available in Africa, Middle East and elsewhere. Indigenous ferrocement sheets and aerated concrete materials were developed using the indigenous inorganic binders and reinforcement systems, and were characterized. Theoretical models were devised for prediction of the structural attributes of indigenous ferrocement sheets and sandwich composite panels comprising the indigenous ferrocement skins and aerated concrete core. Structural designs were developed for these indigenous sandwich composite panels in typical building systems subjected to either normal (gravity and wind) or extreme (blast, earthquake) loading conditions. Examples of indigenous sandwich composite panels were fabricated using the indigenous construction materials developed in the project, and were experimentally evaluated under out-of-plane and in-plane load systems. Theoretical models were verified using the experimental results generated in the project. Competitive merits of the indigenous materials and building systems developed in the project were evaluated. Numerical modeling capabilities were developed for structural analysis of indigenous building components and structural systems under different loading conditions.

SN Applied Sciences

Concrete is the most widely used construction material. It offers a desirable balance of cost, st... more Concrete is the most widely used construction material. It offers a desirable balance of cost, strength, moisture barrier qualities, and dimensional and chemical stability. The rising costs of aging infrastructure systems, however, point to the need for further improvements in concrete properties. Carbon-based nanomaterials (CBNs) are predicted to have excellent mechanical properties, and so are attractive candidates for addressing these issues. However, the relatively high cost of CBNs, means that only low weight fractions in cement matrices will be economically viable, which presents a significant challenge. The research presented here investigated various surface functionalization techniques for improving the compatibility of carbon nanomaterials (multi-walled carbon nanotubes, carbon nanofiber and graphene nanoplatelets) with cementitious materials in fresh and hardened state. The effects of surface functionalization on the contributions of CBNs to the performance characteristic...

Structural Concrete, 2022

Steel corrosion is a significant problem of concrete‐based infrastructure, and it increases the r... more Steel corrosion is a significant problem of concrete‐based infrastructure, and it increases the repair costs of the damage to structures. Glass‐fiber‐reinforced polymer (GFRP) composite bars are corrosion‐proof and exhibit relatively higher strength than ordinary steel reinforcement. However, GFRP bars degrade when exposed to the highly alkaline environment of concrete over extended periods. This study focuses on the effect of the high alkalinity of concrete on the tensile strengths of several types of GFRP bars. Different accelerated aging techniques were employed to evaluate the effects of GFRP characteristics (fiber volume fraction, matrix composition, bar diameter, and presence of protective coating) on the alkali resistance. The test results indicated that the alkali attack significantly decreased the tensile strength of GFRP, increasing with age. The alkali resistance of the GFRP bars increased up to a fiber volume fraction of 50% but decreased when the fiber volume fraction increased to 60% and above. The effects of protective coating on alkali resistance were generally positive but not consistent, and the effects of the matrix type and bar diameter on the alkali resistance of GFRP bars were insignificant. Accelerated aging did not change the bond strength but altered the failure mechanism associated with the bond failure of the specimens.

SSRN Electronic Journal, 2021

Concrete international, 2017

U ltra-high-performance concrete (UHPC) is an advanced cementitious material with compressive and... more U ltra-high-performance concrete (UHPC) is an advanced cementitious material with compressive and tensile strengths exceeding 150 and 15 MPa (21,760 and 2180 psi), respectively.1-3 UHPC mixtures are generally designed with relatively high dosages of silica fume, high-range water-reducing admixtures (HRWRA or superplasticizer), steel fibers, relatively small concentrations of small-size aggregates, and portland cement typically blended with fly ash or slag cement.4,5 Some distinguishing features of UHPC include an optimized gradation of the granular matter for realizing a high packing density, a water-cementitious materials ratio (w/cm) of less than 0.25, and a relatively high volume fraction of discrete (steel) fibers.6 Production of UHPC mixtures generally requires the use of specialty mixers or extended mixing times to ensure production of a homogenous fresh mixture. The sequencing of the components introduced into the mixer also influences the homogeneity of the fresh mixture. Th...

Case Studies in Construction Materials, 2021

The public reporting burden for this collection of information is estimated to average 1 hour per... more The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggesstions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports,

Juniper Online Journal Material Science, 2017

Since the beginning of the industrial age, the carbon oxide concentration in atmosphere has incre... more Since the beginning of the industrial age, the carbon oxide concentration in atmosphere has increased by about 30% [1,2]. This rise in CO2 concentration has accompanied climate warming with adverse ecological effects. Capture of carbon dioxide for value-added use in hydraulic cement is pursued here to reduce carbon emissions. The use of land filled coal ash as the primary raw material for production of the hydraulic cement developed here offers important environmental benefits. Significant quantities of coal ash, estimated at billions of tons, have accumulated in landfills across the world.

Stavební obzor, Apr 30, 2022

Corrosion is a primary factor compromising the safety and service life of steel structures. Corro... more Corrosion is a primary factor compromising the safety and service life of steel structures. Corrosion protection coatings are generally employed for protection of the steel structures that are exposed to different aggressive environments. This research evaluated the use of biobased ion exchangers as a sustainable means of improving corrosion protection coatings. Two base polymer coatings (vinyl and coal-tar epoxy) were considered. The following types and dosages of biobased ion exchangers were evaluated in these coatings: (i) strong-base ion exchange cellulose in OH, PO4, SiO3, BO3, NO2, SO4 and NO3 forms at 1% by weight of resin; (ii) weak-acid starch citrate ion exchanger in H form at 1 wt.%; and (iii) strong-base ion exchange cellulose in OH form at 2 wt.%. In addition, a strong-base ion exchange resin in OH form was considered at 1 and 2 wt.% as control. Different coating formulations were evaluated based on the outcomes of salt-fog corrosion, moisture resistance, pull-off strength, and abrasion resistance tests. The introduction of certain biobased ion exchangers in protective coatings was found to be an effective means of achieving improved levels of corrosion resistance, adhesion capacity, moisture stability and abrasion resistance.

Civil Engineering Journal, 2017

Aerated concrete materials were developed with abundant natural materials. Aerated concrete can p... more Aerated concrete materials were developed with abundant natural materials. Aerated concrete can provide insulating qualities complemented with secondary structural attributes when used as core in sandwich composites for building construction. A hybrid binder that comprised lime and gypsum was used. Different foaming agents were considered for production of aerated concrete, including saponin that is found abundantly in different plants. Different formulations were considered, and the stability of the foam structure as well as the density and early-age compressive strength of the resulting aerated concrete were evaluated. One formulation comprising lime-gypsum binder with saponin foaming agent, with a density of 0.53 g/cm3, was further characterized through performance of thermal conductivity, split tension, flexure, elastic and shear modulus and sorptivity tests. The results pointed at the satisfactory balance of qualities provided by the aerated concrete when compared with alternat...

ACI Materials Journal, 2017

Construction and Building Materials, 2017

A sandwich composite comprising ferrocement skins was developed as the primary structural module ... more A sandwich composite comprising ferrocement skins was developed as the primary structural module for building construction with indigenous materials. The indigenous reinforcement systems selected for use in ferrocement skins were jute burlap and chicken mesh (flexible galvanized steel wire). These reinforcement systems were characterized through performance of tension tests. The tensile strength, stiffness and ductility of jute burlaps were found to compare favorably with those of chicken mesh which is a viable reinforcement for use in ferrocement. Tension tests on ferrocement sheets indicated that indigenous reinforcement ratios above a threshold level could induce multiple cracking and strain-hardening behavior, producing a desired balance of tensile strength and ductility. The tensile strength of indigenous ferrocements with jute burlap reinforcement exceeded the theoretically predicted values, which could be attributed to the favorable interactions of the burlap reinforcement with the inorganic matrix, and the strengthening effects of hydrates precipitating within the yarn voids in burlap. Experiments were conducted to determine the bond strength and the required development length of the indigenous reinforcement in cementitious matrix. Indigenous sandwich composites comprising ferrocement skins with jute burlap reinforcement and an aerated concrete core made of lime-gypsum matrix and saponin foaming agent were fabricated and subjected to flexure testing. The sandwich composite provided relatively high flexural strengths; the flexural failure modes indicated that the relatively dense aerated concrete core makes important contributions to the flexural performance of the sandwich composite.

Advances in Civil Engineering, 2014

Ultrahigh performance concrete (UHPC) realized distinctly high mechanical, impermeability, and du... more Ultrahigh performance concrete (UHPC) realized distinctly high mechanical, impermeability, and durability characteristics by reducing the size and content of capillary pore, refining the microstructure of cement hydrates, and effectively using fiber reinforcement. The dense and fine microstructure of UHPC favor its potential to effectively disperse and interact with nanomaterials, which could complement the reinforcing action of fibers in UHPC. An optimization experimental program was implemented in order to identify the optimum combination of steel fiber and relatively low-cost carbon nanofiber in UHPC. The optimum volume fractions of steel fiber and carbon nanofiber identified for balanced improvement of flexural strength, ductility, energy sorption capacity, impact, and abrasion resistance of UHPC were 1.1% and 0.04%, respectively. Desired complementary/synergistic actions of nanofibers and steel fibers in UHPC were detected, which were attributed to their reinforcing effects at ...

Construction and Building Materials, 2013

h i g h l i g h t s Durability performances of dry-cast concrete mix with graphite nanoplatelet w... more h i g h l i g h t s Durability performances of dry-cast concrete mix with graphite nanoplatelet were evaluated. Graphite nanoplatelets were surface modified to improve their dispersion in mixing water. Improvements in durability characteristics of concrete pipes were realized by adding of nanomaterial.