Effect of bacteria on strength, permeation characteristics and micro-structure of silica fume concrete
Construction and Building Materials
Abstract Influence of bacteria on strength and permeation characteristics concrete incorporating ... more Abstract Influence of bacteria on strength and permeation characteristics concrete incorporating silica fume (SF) as a substitution of cement has been investigated in this study. The cement was partially substituted with 5, 10 and 15% SF and with constant concentration of bacterial culture, 10 5 cfu/mL of water. Cement was substituted with silica fume in concrete by weight. At 28 d, nearly 10–12% increase in compressive strength was observed on incorporation of bacteria in SF concrete. At 28 d, the compressive strength of concrete increased from 32.9 to 36.5 MPa for SF, 34.8 to 38.4 MPa for SF5, 38.7 to 43.0 MPa for SF10 and 36.6 to 40.2 MPa for SF15 on addition of bacteria. Water absorption, porosity and capillary water rise reduced in the range of 42–48%, 52–56% and 54–78%, respectively, in bacterial concrete compared to corresponding nonbacterial samples at 28 days. Reduction in chloride permeability of bacterial concrete was observed and the total charge passed through bacterial concrete samples reduced by nearly 10% compared to nonbacterial concrete samples at 56 d of age. At 28 d, total charge passed through concrete reduced from 2525 to 1993 C for SF, 1537 to 1338 C for SF5, 961 to 912 C for SF10 and 1186 to 1174 C for SF15 on addition of bacteria. Calcite precipitation on addition bacteria and confirmed by SEM and XRD analysis is considered as the reason for improvement in properties of concrete. Economic study of bacterial SF concrete has also been carried out in the present work. The Benefit/Cost Ratio of bacterial SF concrete got reduced with the increase in SF quantity. Compared to control concrete, bacterial SF concrete containing 10% silica fume demonstrated highest benefit in improvement in its properties and corresponding highest Benefit/Cost Ratio.
Research Journal of Chemistry and Environment (47) below the critical concentration. The carbon c... more Research Journal of Chemistry and Environment (47) below the critical concentration. The carbon content ranges from 0.23 to 1.01kg/ha. The available nitrogen was in lower range 45 to 337.5 kg/hector. This might be due to high range of mineralization due to high temperature (dry zone) and loss of nitrogen in the form of ammonia. The soil available phosphorous content ranged from 15.00 to 48.9 kg/hector which was medium in range. The available potassium ranged from 115 to 592kg/hector which was high range in all the grape fields.
Solar photo-catalytic treatment of textile wastewater for biodegradability enhancement
International Journal of Environmental Engineering, 2009
... Anita Rajor (Lecturer, Thapar University, Patiala, India), Dr. SN Lall (Principal, HCST, Fara... more ... Anita Rajor (Lecturer, Thapar University, Patiala, India), Dr. SN Lall (Principal, HCST, Farah, India), Dr. RC Maheswari (Head, Biotechnology ... Neppolian, B., Sakthivel, S., Arabindoo, B., Palanichamy, M. and Murugesan, V. (2001) 'Kinetics of photocatalytic degradation of reactive ...
Advancement in concrete technology in recent years is generally focused on the strength of concre... more Advancement in concrete technology in recent years is generally focused on the strength of concrete. Along with strength, durability is also an important parameter needs to be considered during the design of concrete. Inclusions of supplementary cementitious materials refine the pore structure and degree of hydration of the concrete. Silica fume, a by-product generated during reduction of quartz with coal in electric furnace in the production of ferrosilicon and silicon alloys, can be used as partial cement replacement. Along with cementitious materials several additives are acts as sealing agents that seals the pores and cracks thus reduces the permeability but the additives may be incompatible with type of cement, susceptible to ultra violet radiations and expensive.
Influence of Fungus on Properties of Concrete Made with Waste Foundry Sand
Journal of Materials in Civil Engineering, Apr 1, 2013
ABSTRACT Waste foundry sands (WFSs) represent the highest amount of solid wastes generated byfoun... more ABSTRACT Waste foundry sands (WFSs) represent the highest amount of solid wastes generated byfoundries. The high cost of landfilling and the potential uses of waste foundry sand in construction purposes have prompted research into their beneficial reuse. Microbial modified mortar/concrete has become an important area of research for high-performance construction materials. This study investigates the effects of fungal (Eupenicillium crustaceum) treated waste foundry sand on concrete properties as partial replacements of sand. It shows an increase in compressive strength up to 24% and decreases in water absorption (44%) and porosity (50%) in concrete made with fungal treated 20% WFS after 28 days of curing, compared to untreated concrete made with 20% WFS. The strength improvement is attributable to microbially induced mineral formed by fungi, often referred to as calcified filaments, confirmed by scanning electron microscopy and energy dispersive spectra. The formationof calcium oxalate (weddellite) in urease broth by fungi was confirmed by X-ray diffraction. This ability of fungal culture to form the biomineral results in improvements to concrete properties.
Solid waste management has become one of the global environmental issues, as there is continuous ... more Solid waste management has become one of the global environmental issues, as there is continuous increase in industrial by-products and waste materials. Due to lack of land filling space and its ever increasing cost, utilization of waste material and by-products has become an attractive alternative to disposal. Waste foundry sand (WFS) is one of such industrial by-product which could be used in various applications including construction materials such as Controlled Low-Strength Material (CLSM) and concrete. The beneficial use of such by-products in construction materials results in reducing the cost of construction materials’ ingredients and also helps in reducing disposal problem. The leachate obtained from such materials may contain hazardous compounds, which may possibly effect the environment. So, it is important to know the characteristics of leachate obtained from waste foundry sand.Understanding the leachate characteristics of WFS is essential in its disposal, environmental impact, and potential development for beneficial utilization towards solid waste management. This paper describes the physical, chemical properties of WFS, various leachate test methods, and research published on leachate characteristics of waste foundry sand.
Over the past decade, the consumption of heavy metals and chemicals in the process industries has... more Over the past decade, the consumption of heavy metals and chemicals in the process industries has increased dramatically. Heavy metals are valuable resources for different industrial applications but their contamination in environment is a major global concern because of toxicity and threat to human life and environment. So, the recovery and recycling of heavy metals and the strict environmental regulations compel the industries to shift to cleaner production method, demanding the development of environmental friendly, low cost and efficient treatment techniques for metal rich effluent. Microorganisms can remove heavy metals by the process of bioaccumulation which is cost effective and eco-friendly as compared to conventional methods. The present study was carried out on bacterial isolates from electroplating unit effluent to check their potential for removal of chromium and nickel from aqueous solution containing single heavy metal. The effluent, soil and sludge samples were collected and analyzed for physico-chemical properties which were then used for isolation of nickel and chromium tolerant bacteria. The morphological and cultural characteristics of the isolates were studied and a special staining method was used to observe the concentration of metals within the cells. Growth study of the bacterial isolates showed that the toxicity of metals in medium (having metal) could not support the growth of bacteria. Reduction of metal content in medium with time was observed and indicates that the bacteria have an intrinsic ability to absorb metals from solutions. Upto 38.3% and 40.0% removal of nickel in nutrient medium and minimal media respectively and upto 64.0% and 69.0% removal of chromium in nutrient medium and minimal media respectively, were observed. Hence it can be concluded that the bioaccumulation is efficient and cost effective eco-friendly process and the isolated bacterial strains, which can tolerate high concentration of heavy metals, can be utilized for metal recovery process.
I ft.ru -ffi.engineered" that more efficiently synthesize PHAS and will bring the cost down to ma... more I ft.ru -ffi.engineered" that more efficiently synthesize PHAS and will bring the cost down to make PHAs competitive with the synthetic plastics.
Advancement in concrete technology in recent years is generally focused on the strength of concre... more Advancement in concrete technology in recent years is generally focused on the strength of concrete. Along with strength, durability is also an important parameter needs to be considered during the design of concrete. Inclusions of supplementary cementitious materials refine the pore structure and degree of hydration of the concrete. Silica fume, a by-product generated during reduction of quartz with coal in electric furnace in the production of ferrosilicon and silicon alloys, can be used as partial cement replacement. Along with cementitious materials several additives are acts as sealing agents that seals the pores and cracks thus reduces the permeability but the additives may be incompatible with type of cement, susceptible to ultra violet radiations and expensive.
The present study has been undertaken to evaluate performance efficiency of an Effluent Treatment... more The present study has been undertaken to evaluate performance efficiency of an Effluent Treatment Plant (ETP) of a textile industry located in Narol , Ahmedabad (Gujarat). An effluent treatment plant is operating on Conventional Effluent treatment method with an average wastewater inflow of 630 m3/day. has been considered for case study. The wastewater is analyzed for the major water quality parameters, such as pH, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) Total Dissolved Solids (TDS),Total Suspended Solids (TSS)and Ammonical Nitrogen (NH 3 -N) The composite samples were collected on a hourly basis for one day . The raw wastewater pH was highly alkaline it was then bringing down to neutral which was helpful for biological treatment. The BOD, COD, TDS, TSS, NH3-N of the treated effluent reduced significantly, where as very small reduction was observed in dissolved solids (61.25 %). Most of all the parameters were above the permissible limits of Gujarat Pollution Co...
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