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• Novel analysis of attenuation the growth of Aspergillus tamarii on concrete using radiation in the field of conservation of heritage building. • UVC and gamma irradiation decreased the leaching of calcium ions from concrete when infected with A. tamarii. • Increase in compressive strength of concrete cube was observed to be the most in irradiated cubes. • Effect of A. tamarii and low dose radiation led to less deterioration of concrete (except higher dose) than only exposure to A. tamarii. The conservation of concrete-based deteriorated heritage buildings is a big challenging issue worldwide including in India. This study focused on to prevent fungal biodeterioration in concrete using UVC and gamma radiation. M20 graded concrete cubes (5 cm × 5 cm × 5 cm) were infected with Aspergillus tamarii , which was isolated from a 200 years old historic heritage building. M20 signifies a mixture of cement, sand and aggregate (1:1.5:3), made in such a way that the concrete cube has a compressive strength of 20 N/mm2 when examined after 28 days of curing. The fungal growth appeared clearly as calcium oxalate crystals in the Scanning Electron Microscope (SEM) photographs. Several doses of UVC and gamma radiation were applied on concrete cube. The changes in concrete properties were examined after 30 days in terms of weight, compressive strength, Fourier Transform Infrared Spectroscopy (FTIR) and micro Energy Dispersive X-ray Fluorescence (EDXRF). The results exhibited that compressive strength of control (non-infected and non-irradiated), biodeteriorated (infected), UVC (625 µw/cm² × 300 s) and gamma (0.5 KGy) irradiated infected (inhibition) concrete cubes were 19.74 ± 0.46, 18.88 ± 0.43, 20.20 ± 0.34 and 19.93 ± 0.20 N/mm2 respectively whereas negligible weight losses were observed for inhibition cubes compared to biodeteriorated ones. Calcite (1400, 874 and 705 cm−1), one of the major functional band present in concrete became weak after getting infected by Aspergillus tamarii and strong for inhibition samples irradiated with the above doses. The EDXRF analysis exhibited that mass percentage of calcium ions of the biodeteriorated concrete cubes (49.88 ± 0.65%) was lower than that of UV (75.75 ± 0.16%) and gamma (70.95 ± 0.30%) irradiated infected or inhibition concrete cubes. Altogether, the efficacy of the recommended inhibitory dose of ultraviolet and gamma radiation against concrete deterioration in the field of conservation of heritage building was observed to be positive. [Display omitted] [ABSTRACT FROM AUTHOR]

Induration of ilmenite pellets by oxidation is an essential step in the pelletization process since it decides the physical and metallurgical properties of the pellets. In this regard, the induration parameters such as temperature and roasting time have been optimized to obtain good quality ilmenite pellets made of concentrates obtained from low-grade ilmenite ores of Odisha, India. The oxidation temperature of 900 °C at a short roasting time of 15 min has been found suitable to achieve recommended requirements of various pellet properties such as cold compressive strength, porosity, metallization, tumble, and abrasion indices. X-ray diffraction and microstructural analysis indicate that the recrystallization of hematite in the oxidation process improves the mechanical strength of the pellets. In contrast, the formation of ferric pseudobrookite phase at 1000 °C and 1100 °C oxidation temperatures impairs the pellet strength. Unlabelled Image • The readiness of the ilmenite pellets for the reduction process was assessed through induration studies. • Different metallurgical properties were analyzed as a function of temperature and time. • Desirable pellet properties were attained at a temperature of 900 °C and a period of 15 min. • The phases changes occurred during induration were clarified using in-depth XRD, SEM, and EPMA analyses. • The oxidation mechanism of ilmenite pellets was correlated to the pellet consolidation. [ABSTRACT FROM AUTHOR]

The Indian National Gas Hydrate Program Expedition 02 (NGHP-02) was the most comprehensive gas hydrate drilling expedition carried out to date. From 74 pressure cores that were successfully recovered from various site locations offshore India, 19 subsamples were obtained for further detailed geotechnical analysis using the PCATS Triaxial apparatus to investigate the geomechanical behaviour of the cores, including small-strain stiffness, G max , undrained shear strength, S u , as well as direct-flow measurements of permeability, k. Samples tested included fine-grained muds with no appreciable hydrate through to coarse-grained sands that contained extensive hydrate within the pore space. Although the subsampling and transfer of pressure cores into the PCATS Triaxial under zero effective confining stress, σ′ , remains challenging, 12 samples were successfully transferred and underwent detailed geotechnical characterization. During consolidation, after reapplication of in-situ σ′ , all samples experienced axial and radial consolidation, with variations between samples seemingly dependent on the degree of sample disturbance, stress relaxation between coring and testing, hydrate saturation, S h and grain size, D 50. The largest values of G max were obtained from samples with high S h in the pore space, with values much higher than that expected for similar sediments without hydrate under comparable σ'. Samples with high permeability had both high S h and larger grain size, suggesting that in coarse-grained sediments sufficient pathways are available for reasonable fluid flow even with high hydrate saturations. Triaxial testing and unconfined compression tests highlighted the influence of hydrate on increasing sediment strength, although the size of the sediment grains appeared to have an important control on the magnitude of the strength increase and the overall stress-strain behaviour. The results from the detailed geotechnical characterization of the recovered pressure cores will be invaluable in helping India identify potential locations for future gas production wells, and assess the long-term performance of such reservoirs. • Testing of pressure core samples using PCATS Triaxial apparatus was undertaken. • Induced strains during consolidation are influenced by test and sample conditions. • Permeability of hydrate-bearing sediments are greater than fine-grained sediments. • Hydrate cement increases strength/stiffness of coarse-grained sediments. • Increases in strength/stiffness influenced by grain size and clay content. [ABSTRACT FROM AUTHOR]

For practical reasons, it is typical for different types of sheathings (referred to as dissimilar) to be connected at both flanges of the stud (lipped channel-section) in cold-formed steel (CFS) panelized construction (e.g. one side has interior sheathing and the other exterior sheathing). However, limited studies are available on the axial behaviour of CFS studs with different combinations of sheathings present at both-flanges of a stud. This novel experimental study investigates the structural behaviour of nineteen (19) CFS panels with sheathing on one side only and different sheathing on both flanges of the wall panel using combinations of eight (8) different sheathing board types [fibre-cement boards (FCB) (8 mm/10 mm/12 mm thick); calcium silicate boards (12 mm thick); orient strand board (12.5 mm thick); and heavy duty FCB (6 mm/9 mm/12 mm thick)]. Also, first time an attempt is made to study the effect of dissimilar configuration using eight (8) different sheathing board types on axial strength of CFS panels in India. Experimentally tested single stud wall panel specimens consist of; one bare single-stud; eight (8) specimens sheathed with different types of sheathing boards on one flange only; and ten (10) specimens with combinations of different sheathing boards on both-flanges. Average test results are obtained by performing two (02) tests for each specimen. The strength enhancement of a bare single-stud from the sheathing boards has been investigated by testing specimens with a single layer of sheathing at one-flange and combinations of different sheathing boards on both-flanges. The ultimate axial compressive strength, load–deformation behaviour and failure patterns are the parameters compared. A new analytical and semi-analytical design methodologies namely; Rayleigh–Ritz (R-R) method and finite-strip method based on direct strength method (DSM) are adopted for evaluating the axial compressive strength of the CFS wall panels with dissimilar sheathing. Limited studies are available to verify the efficacy of R-R method and DSM to estimate the axial compressive strength of CFS wall panels with dissimilar sheathing on both flanges. Results establish that DSM may be used efficiently rather than the R-R method for axial compressive strength prediction of dissimilar sheathed CFS wall panels. The predicted values show good agreement with the experimental test results, and therefore, demonstrate that the semi-analytical method may be applied efficiently in design. • First time an attempt is made to study the axial compressive behaviour of CFS panels with dissimilar sheathing in India. • A total of 19 axial compressions tests were carried out on single-studded CFS wall panels with dissimilar sheathing. • Bare stud, one-flanged and both-flanged specimens using 8 different sheathing boards were considered for testing. • Tests were carried out on sheathing boards to evaluate the modulus of elasticity and peak deformation at failure. • Performance assessment of the Rayleigh–Ritz and Direct Strength Method is carried out using the experimental results. [ABSTRACT FROM AUTHOR]

• Indian finely grounded waste glass powders (GP) recycling in M30 and M40 grade concretes. • GP as cement replacement from 0 to 40%, steps of 10% • Workability, compressive strength and durability indicators improved with the increased of GP content. • Increased drying shrinkage with GP content, still within standard limits. • 30% GP as cement replacement provides optimal engineering properties for conventional concretes and paver concrete blocks. Waste glass is a significant concern in India, and management solutions seek. Finely ground waste glass (GP) presents pozzolanic properties, which make it potential for concrete applications as cement replacement. The main feature of the present work lies in the simultaneous incorporation of two GPs with different fineness, generated from consumer scrap in India, as cement replacement in equal proportions, from 0 to 40 %, in two concrete grades, M30 and M40. An experimental programme was carried out, including fresh, shrinkage, mechanical and durability properties. GP concrete specimens showed compressive strength and a slight improvement for both concrete grades compared to reference concrete specimens (0 % GP incorporation). The durability indicators, namely, water absorption, sorption, chloride-ion penetration and moisture movement in GP concrete, improved with the increase of GP content. The drying shrinkage increased with the rise in GP content; however, the results still fit the permissible standard limits. Optimal concrete mixtures were selected to further study GP incorporation in concrete paver blocks. Four concrete paver block types were produced, including M30 and M40 with no GP (0 %GP) and M30 and M40 with 30 % GP as cement replacement (15 % GP1 + 15 % GP2). The compressive strength of the concrete paver blocks with GP significantly improved. Thus, the concrete with 30 % partial cement replacement by GP is a potential option for the construction industry while providing a management waste solution and contributing to a circular economy. [ABSTRACT FROM AUTHOR]

Coal fired thermal plants in India produce about 131 million tons of coal ash, which comprises about 25 million tons of coal bottom ash. Utilization of coal bottom ash has environmental advantages also which are of great importance in the present context of sustainability of natural resources. The replacement of river sand with industrial by-products such as coal bottom ash in concrete can prove both technically and economically beneficial to the construction industry. In this study, laboratory tests were conducted to assess the possibility of the use of coal bottom ash as a substitute material of river sand in concrete. River sand was substituted with coal bottom ash by mass in concrete at 0, 30, 50, 75 and 100% replacement level. The test results show that 28 d compressive strength and pulse velocity through concrete were not affected on the use of coal bottom ash in concrete. Water absorption and initial rate of absorption of water by capillary action increased on incorporation of coal bottom ash in concrete manufacturing. However, the secondary rate of absorption of water was constant for all concrete mixtures. Water absorption varied between 4.68 and 5.56% for all concrete mixtures at curing period of 28 d. With increasing age, bottom ash concrete mixtures showed significant reduction in permeable pore space and water absorption. Abrasion resistance was measured in terms of average depth of wear. Bottom ash concrete mixtures displayed marginally lesser resistance to abrasion than control concrete. All the concrete mixtures showed decrease in the average depth of wear with increasing age, in other words increase in resistance to abrasion. [ABSTRACT FROM AUTHOR]

Abstract: A novel hot spring bacterial strain was isolated and characterized from Bakreshwar, West Bengal, India. Phylogenetic analysis of partial 16 S-rRNA gene sequence (697 nucleotides) suggested that the isolate was affiliated with the family ‘Firmicutes’ and 99.8% homologous with Thermoanaerobactor thermohydrosulfuricus. A unique thermostable and high pH tolerant protein (28kDa) secreted by the bacterium was isolated whose N-terminal partial sequence (25 AA) suggested that the protein was similar to mammalian carbonic anhydrase-II. This bacterium or its unique protein both increase the compressive (>25%) and tensile (>20%) strengths, hardness and elastic modulus of cementitious material when incorporated to the cement/cement–sand mixture. The protein (named as bioremediase) possesses silica leaching activity, which is increased by calcium ions. No esterase and/or proteolytic activities are present in the protein. The use of such isolated bacterium or its protein in concrete technology develops new construction material that may be used for self-healing concrete in future. [Copyright &y& Elsevier]

Sewage sludge (SS) management has been regarded as a serious environmental and health issue around the globe, especially in developing countries like India, mainly due to the lack of proper regulatory criteria, and appropriate engineering infrastructures. The present research work demonstrates the utilization of Fly Ash (FA) in varying percentages (with an interval of 10%) with SS as brick for sustainable building material with special emphasis on dimensional Effect. The impact of dimensional effect is measured using compressive strength behaviour for a stress rate of 14 MPa/min of two different sizes of brick i.e. D1 and D2 of sizes 7 × 7x7 cm3 and 2 × 2x2 cm3, respectively. Owing to the sintering effect, the maximum strengths of 4.02 MPa and 7.6 MPa are noticed for a composition of 60% SS+40% FA for D1 and 40% SS + 60% FA for D2, respectively. According to the Indian Standards (IS) 13757: 1993, an exhibited strength of more than 3.5 MPa by any brick composition enables it to be used as a common building brick. In general, due to the formation of triangular wedges, the D2 bricks exhibited better strength for any mixing ratio of FA and SS. The added benefit in our study was lower thermal conductivity (0.48 Wm−1K−1) of the prepared fired brick implying its better insulation property. Our study uniquely highlights the possible utilization of FA for stabilizing SS for sustainable substitution of natural clay fired brick. Future study may further investigate the compositional effect of FA on the thermal and thermodynamic attributes of the bricks. Image 1 • Pioneer study on bricks that visualizes dimensional effect along with mechanical properties. • 40–60% fly ash with sewage sludge satisfies Indian codal provisions as construction material. • Thermal conductivity of synthesized brick is lower than conventional fired clay bricks. • Dimensional effect significantly influences the compressive strength behaviour. [ABSTRACT FROM AUTHOR]

The mining of natural material such as sand on large scale for use in construction of infrastructure in developing countries like India is posing threat to the environment. To save the environment, therefore, it becomes obligatory on the part of researcher to explore the utilization of industry by-products in place of natural material. In this study utilization of saw dust generated by wood industry in concrete has been explored. This article presents properties of concrete using different percentage of water and sodium silicate treated saw dust as replacement of sand. Saw dust passing through 4.75 sieve was treated with water and sodium silicate for 24 h before using in concrete. Natural sand was replaced with 5, 10,15 and 20% water treated saw dust in concrete mixture. The effect of silica fume on properties of concrete containing 5% water treated saw dust was also studied by replacing 4, 8 and 12% cement with silica fume in concrete. It was observed that concrete made with 5% water or sodium silicate treated saw dust displayed compressive strength comparable to that of control concrete. However, for 10% replacement level, compressive strength and split tensile strength decreased by 30.30% and 32.19% respectively, at 28 days. Total charge passed, water penetration and capillary water absorption increased by 224%, 153% and 117.4%, respectively, on use of 10% treated saw dust. The concrete mixture modified with sodium silicate treated saw dust showed remarkable improvement in respect of resistance to chloride ion penetration. As expected, the results showed considerable decrease in density of concrete with the use of saw dust as replacement of sand. Addition of sodium silicate treated saw dust resulted in ettringite formation in large quantity in concrete. • Sand in concrete was replaced with 5, 10, 15 and 20% water treated saw dust. • The optimum quantity of water or sodium silicate treated saw dust is 5%. • Density of concrete decreased on use of saw dust. • Strength properties of concrete modified with 5% saw dust is comparable. • Chloride ion permeability improved on silica fume in saw dust modified concrete. [ABSTRACT FROM AUTHOR]

• Mechanical strength and pore properties are checked with over burnt brick aggregate. • Nonlinear relation is obtained among permeability, porosity and compressive strength. • For single sized aggregates, permeability lie in the range of 1.2–2.1 cm/s. • Prediction equations are made for porosity, permeability and compressive strength. In the search of alternate construction materials, over burnt brick aggregate has enrolled its appellation as a low cost sustainable alternate material. In the north-eastern part of India, especially in Tripura, the shortage of natural stone aggregate has opened up the field for over burnt brick aggregate to be used as an alternate pavement material. This study mainly focuses on the characterization of pervious concrete mixes produced with over burnt brick as coarse aggregate. Pervious concrete, in the recent era, has been considered as the emergent technology due to its prominence as an environmentally and hydrologically sustainable pavement system. In this paper, a series of test samples are produced using various design variables and then the mechanical strength and the pore properties of porous mixes are evaluated. Aggregate gradation, water-cement ratio and the percentage of fine aggregate are chosen as the design variables and their effect in the compressive strength, tensile strength, flexural strength, porosity, permeability, etc. are estimated. The statistical analysis is also carried out using the experimental test data and prediction equations are developed to estimate the porosity, permeability and the compressive strength of the pervious concrete mixes. The predicted equations fitted well and showed a very good agreement with the calculated results. These equations can be directly used for the selection of the mix proportion and the designing of pervious concrete mixes made with over burnt brick aggregate. [ABSTRACT FROM AUTHOR]