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HIGH PERFORMANCE ALKALI ASH MATERIAL
Hossein
Rostami Sally
Solomon ABSTRACT
Alkali
Ash Material (AAM) AAM has advantages over other concrete products. AAM can be used to create high performance concrete (AAM-HPC), providing rapid strength gain and development of high ultimate strengths of more than 110 MPa. AAM has far better environmental resistance than Portland cement concrete, resisting attack from sulfuric acid (H2SO4), hydrochloric acid (HCl), and organic acids. AAM resists freeze-thaw attack and high abrasion, possesses low chloride permeability and does not exhibit alkali silica reactivity. AAM concrete is mixed and molded like ordinary Portland cement using conventional technology, adapted from existing facilities in manufacture of pipe, block and wet cast concrete products. AAM hardens with dry curing, whereas Portland cement is hydrated and requires moist curing. Applications of AAM are blocks, pipes, median barriers, sound barriers, overlaying materials, and chemical resistant products. With further development, AAM will be suitable for bridge beams, concrete tanks, highway appurtenances, and other high strength construction products. Keywords: Fly ash, alkali activation, recycling, high performance concrete, chemical resistant
STUDY OF PARAMETERS INFLUENCING THE PROPERTIES OF SINTERED
FLY ASH AGGREGATES
K.I.
Harikrishnan Dr.
K. Ramamurthy* Building
Technology and Construction Management Division
Phone No.: +91-44-22578309 Fax: +91-44-22578281 ABSTRACT
Pelletization is a promising process for making artificial aggregates from fine-grained materials like fly ash, which facilitates its high volume utilization as lightweight aggregate in concrete. A review indicates that only limited studies are reported on pelletization of fly ash aggregates. A study on the process of pelletization for the influences of angle of pelletizer disc, moisture content, affect of fineness of fly ash, and sintering temperature and its duration was undertaken. The salient observations are; i) for a chosen diameter of the pelletizer disc and the speed of revolution, the optimal angle of pelletizer has to be determined to maximise the pelletization efficiency, ii) adjustment of moisture content results in production of pellets of different size, and iii) for a given temperature and duration of sintering, pellets made with finer fly ash yield relatively higher strength.
STABILITY OF VERTICALLY STACKED RED MUD DISPOSAL CELLS
Joseph
Sai Texas A&M
University-Kingsville ABSTRACT
This study was conducted to determine the feasibility of dry stacking bauxite waste to a height of 70 feet (21.3 m) with minimal adverse effect on the integrity of the disposal facility. Red mud samples were obtained from a disposal facility and analyzed for their geotechnical properties, (i.e. confined consolidation, unconfined shear strength, Atterberg limits, specific gravity, etc). Data from these analyses were used to predict the stability of different heights for stacking red mud in the storage facility. Slope stability analysis using Rotational Equilibrium Analysis of Multi-Layered Embankments (REAME2k) software showed that the disposal facility is stable under the present loading condition, and at the proposed peak elevation of 70 feet (21.3 m) above mean sea level (MSL). The simplified Bishop, Spencer, and Modified Spencer methods indicated a minimum factor of safety against failure of 1.4 to 1.6. These values are somewhat above industry standard of 1.3 and indicate the facility could safely load red mud wastes to the proposed height of 70 ft (21.3 m) above MSL with diligent field monitoring during and after waste placement to confirm software output. Keywords: Red mud; bauxite; dry stacking; slope stability; waste disposal; factor of safety
IDENTIFYING OPPORTUNITIES FOR IMPROVING THE MANAGEMENT OF WASTE WITHIN A UK, ACUTE HOSPITAL USING A SYSTEMS ANALYSIS APPROACH Anne
C. Woolridge Paul
S. Philips University
College Northampton, Park Campus ABSTRACT
Waste generation, segregation and disposal were monitored, using observation and interviews, in a number of general wards in an UK Acute Hospital of 650 beds. The data was analysed using a structured systems analysis approach based upon Structured Systems Analysis and Design Method (SSADM). An initial Data flow Diagram, produced using SSADM, was developed into a Waste Flow Diagram, which was used to document waste generation, flow and disposal within the hospital. The Diagram tracks the movement of waste through the system and helps identify the appropriate disposal stream for a given object. Such an approach enables managers to identify cost savings through effective identification, segregation and consignment to the appropriate disposal option. The SSADM approach produces a tool that supports the adoption of best practice, as the visual outcomes enable senior managers to devise training schemes for staff in sustainable waste management within a hospital context. This study, quickly identified savings (£28 099 per annum) that were some 18% of the clinical waste costs of the hospital. Detailed application within an UK hospital would be expected to lead to significant savings with all waste streams as well as reducing costs for general resource management such as food provision and stock control. Keywords: Healthcare waste, clinical waste, systems analysis, hospital, waste flows
SLUDGE HOMOGENISATION FOR IMPROVED ENERGY AND REDUCED
SLUDGE PRODUCTIONS
Theodore
I. Onyeche ABSTRACT
Sewage sludge is still a major concern to mankind. The environmental and health problems caused by the contaminants in sewage sludge have led to intensified research and development activities worldwide. Sludge is a residue/product from wastewater treatment plants and contains most of the contaminants released during man's activities. The management of sewage sludge is one of the major challenges in the wastewater treatment industry and one of the most important economic and environmental issues for the next decade. Some stringent environmental regulations on sludge treatment and disposal have been imposed in several countries. These have resulted in an increasing interest in processes allowing the reduction in sludge and improvement in biogas production during the anaerobic digestion process. This work shows the first exploitation of valuable energy from stabilised sludge with subsequent mass reduction at technical scale after using a specially modified high-pressure homogeniser led to the success of this unique project. Results showed that about 30% more energy (i.e. methane gas) could be obtained from concentrated and disrupted sludge than from untreated samples. The energy produced was higher than that invested during disruption and digestion processes. About 23% sludge reduction was also observed with no increase in chemical oxygen demand which confirms the earlier laboratory results already published in volume 29 (February 2003) of this same journal. This new process can produce extra energy for local electric supply, for heating the digester while the sludge reduction provides savings for the plant operators depending on the size, type and location of the plant. Concentration of sludge causes reduction in investment cost on digester as well as reduction in operational time for sludge dewatering. Keywords: Sludge, concentration; digestion; disruption; disintegration; high-pressure homogeniser; sludge
A METHODOLOGY FOR COMMUNITY BASED WASTE MANAGEMENT
DECISIONS
A. Morrisey
J. Browne ABSTRACT
Keywords: Sustainable waste management; decision support; methodology; policy; community
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