1.

Investigation For Curling Stress In Self Compacting Concrete Pavement

Authors: Mr. Dilip Kumar Rawat, Abhishek Kumar, Isai Ganesh, Abhishek Kumar

Article Type: Research Article
Published: June 2020
Pages: 01–23
DOI: 13.3765/je-2020-144
Abstract
Abstract

A Highway asphalt is a construction comprising of . layers .materials over the regular soil layer. In India, adaptable asphalts are liked for street development because of lower development expenses and expedient development when contrasted with inflexible asphalts. However, the maintenance costs of the rigid pavements are relatively lower as compared to the maintenance costs of flexible pavements. The rigid pavements are constructed by casting cement concrete slabs over dry lean concrete or granular sub-bases. The cement concrete pavements are designed to withstand traffic loads and environmental loads during its service life. The environmental factors that are considered in the concrete pavement analysis are temperature, humidity, precipitation and frost/heave. The stresses induced in the concrete pavements on account of daily temperature variation are termed as curling stress. The curling stresses are as important as axle loads in the concrete pavement analysis as they alone can trigger the failure of the cement concrete pavements. The rigid pavements are constructed with normally vibrated concrete. Self-compacting concrete (SCC) is preferred over normal concrete mainly due to improved mechanical properties and speed of construction. Due to environmental regulations and concerns, the use of natural river sand in concrete manufacture is becoming impractical and obsolete. Nowadays crushed sand is widely used in concrete manufacturing process. Hence, the properties of SCC mix prepared with natural sand and crushed sand were tested in the present research. SCC is a concrete with high binder content, which poses a challenge from the point of view of sustainability. Thus, use of pozzolanic materials like fly ash and its effect on the properties of SCC were also investigated. In the present study, 20% Class C fly ash dosage as a cement replacement material was obtained through experimental trials. The thermal properties of concrete are influenced by the thermal properties of the matrix and aggregate phase. The coarse and fine aggregates utilised in the current investigation were of granitic origin. When compared to concrete made with aggregates of various minerals, the thermal characteristics of concrete made with granite based aggregates are quite high. The effect of perlite, a well-known insulating substance, as a fine aggregate substitute on the The characteristics of SCC mix were also investigated. The dosage of 5% perlite as a fine aggregate replacement material was evaluated experimentally in this study.

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3.

Influence of Incubation Temperatures on Total Phenolic, Flavonoids Content and Free Radical Scavenging Activity of Callus from Heliotropium Indicum

Authors: Muthusamy Senthil Kumar, Srinivasan Balachandran, Shibani Chaudhury

Article Type: Research Article
Published: June 2020
Pages: 01–05
DOI: 13.3765/je-2020-145
Abstract
Abstract

The incubation temperatures such as 20, 25, 30 and 32°C were used on callus culture of Heliotropium indicum L. for assessment of total phenolic, flavonoids content and free radical scavenging activity. The callus biomass was decreased in the treatments than the control (1.92 ± 0.01 g/tube). The texture of the callus (compact) was same in all the treatments but the colour was slightly different. The highest amount (10.29 ± 0.09 mg/g) of total phenolic content was estimated from callus grown under 30°C. Callus from the same treatment shows maximum percentage (53.17 ± 1.43) of free radical scavenging activity.

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