ABSTRACT
Within concrete engineering, the uptake of self-compacting concrete (SCC) represents a notable trend, delivering improved workability and placement efficiency. However, challenges persist, notably in achieving optimal performance while mitigating environmental impacts, particularly in cement consumption. However, simply reducing the cement content in the mix design can directly compromise the structural-concrete requirements. Towards these challenges, global trends emphasize the utilization of appropriate waste materials in blended concrete. This study explored a promising strategy by integrating supplementary cementitious materials (SCMs) to contribute to the United Nations' Sustainable Development Goals (SDGs) in addition to the engineering contributions. It suggests an optimal combination of Metakaolin (MK) and Limestone Powder (LP) to partially substitute cement. The research methodology employs the response surface method (RSM) to systematically explore the ideal ingredient ratios. Through a comprehensive analysis of orthogonal array of 16 mixes, encompassing both mixture and process variables, this study aims to explain the effects of MK and LP addition on the rheological and mechanical properties of SCC with varying cement replacement levels. In terms of mixture constituents, the total composition of cement, MK, and LP was fixed at 100%, while coarse aggregate (CA), fine aggregate (FA), and the water-to-binder ratio were held as process variables. In order to assess the rheological properties of the mix-design, various tests including slump flow, L-box, and sieve segregation were conducted. Additionally, to evaluate mechanical strength, samples were tested for compressive strength at both 7 and 28 days. Findings from the experiments reveal higher concentrations of MK result in reduced workability and hardened properties. Through RSM-based designed experimentation covering both rheological and mechanical aspects, it is observed that the optimal cement replacement level lies between 40 and 55%. The findings of this study contribute to the advancement of sustainable and structurally robust concrete practices, offering insights into the optimal utilization of SCMs to meet both engineering requirements and environmental sustainability goals.
ABSTRACT
The aim of this project was to improve the Aspergillus terreus strain and pretreatment of sugarcane bagasse as carrier substrate for bulk production of lovastatin, a cholesterol-lowering drug, in solid state fermentation. Sugarcane bagasse was treated with alkali (1-3% NaOH) for the conversion of complex polysaccharides into simple sugars for better utilization of carrier substrate by microorganism for maximum lovastatin production. Ethidium bromide (time of exposure 30-180 min) was used to induce mutation in Aspergillus terreus and the best mutant was selected on the basis of inhibition zone appeared on petri plates. Fermented lovastatin was quantified by high-performance liquid chromatography. The fermented lovastatin, produced by parent and mutant Aspergillus terreus strain, was checked on body weight, blood glucose and serum cholesterol, ALT, AST, HDL-C, LDL-C, TG and TC levels of rats for their cholesterol lowering capacity. Our results indicate that selected strain along with 2% NaOH treated sugar cane bagasse was best suitable for bulk production of lovastatin by fermentation and fermented lovastatin effectively lower the cholesterol level of rats.
