Utilisation of flyash as cement replacement material to produce high performance concrete

Disposal of fly ash, a waste product from thermal power plants, is a major problem in India.Many R&D and academic institutions are actively involved in the effective utilisation of flyash in Civil Engineering applications. The Structural Engineering Research Centre (SERC),Chennai has carried out extensive research on utilisation of fly ash in concrete as partial cement replacement material (CRM) since 1975 . Recently, SERC has carried out extensive R&D work on development of High Performance Concrete (HPC) mixes using flyash(FA),ground granulated blast furnace slag(GGBS) and silica fume(SF) as mineral dmixtures,especially to improve the durability characteristics of cement concrete. This paper presents the mechanical and urability properties of different HPC mixes containing fly ash. HPCs using flyash as mineral admixture have been used to evelop precast concrete products such as, non-pressure pipes and heavy duty paver blocks and these developments are eported in this paper

ORIENTAL JOURNAL OF CHEMISTRY Evaluation of the Role of Cetyltrimethylammoniumbromide (CTAB) and Acetylenicglycol (AG) Admixture on Fly Ash Based Geopolymer

ABSTRACT Alkali activation of fly ash with proper mix design and correct formulations can exhibit very good strength and chemical resistance and other potentially valuable characteristics similar or even better than conventional Portland cement. Utilization of fly ash activated system as binder material in construction industry can limit the consumption of virgin materials required for the production of cement as well less energy intensive process in the manufacturing stage leads to lower greenhouse gas emission. Goeopolymeric products with characteristic properties can be achieved on a laboratory scale level by optimizing the process conditions using selected source material with the addition of admixture. On contrary, Usage of variable source material in a large scale preparation, issues like flow ability, control of setting time are always present that need to be studied. This study was conducted on leaching of fly ash by hybrid activator solution namely sodium silicate, sodium hydroxide, for preparing geopolymer matrix wherein geopolymer (GPC) mortar was made with the addition of organic admixture Cetyltrimethylammonium bromide (CTAB), Acetylenic glycol (AG) as flow ability enhancer with dosage ranging from 0-2% by keeping the Liquid/Solid as 0.45.The Compressive strength of the mortar in the order 30 Mpa was achieved with good flow property by the addition acetylenic glycol and the zeta potential value was found to be similar in the order of control specimen (-15.4mv). Analysis of SEM microstructure of the matrix revealed that binding gel of type Na-S-H are found to be more on AEG added matrix than that of CTAB

Sulphuric acid resistant ecofriendly concrete from geopolymerisation of blast furnace slag

357-367In this study, geopolymer is prepared from ‘ground granulated blast furnace slag’ (GGBS)–a powder from grinding the by-product of slag waste from blast furnace of steel plants. For comparison, conventional cement, Portland pozzolana cement (PPC) containing fly ash was considered. To achieve simultaneous acidic and sulphate attack, sulphuric acid is used for durability studies. The test data indicate that on exposure to 2% and 10% sulphuric acids, the losses in weight, thickness and strength of geopolymer concrete (GPC) are significantly much less than those for Portland pozzolana cement concrete (PPCC). The GPCs have inorganic polymers of alumino-silicates as binder, generally without any free lime. Therefore, GPCs resist acid attack better than free lime containing conventional concretes containing Portland cement. The binding action in GPC is through geopolymerisation of GGBS using alkaline activator solution (AAS) made of sodium hydroxide and sodium silicate solutions. The geopolymer eliminates use of Portland cement in structural concretes by utilizing the industrial by-product GGBS, thereby reducing considerably the carbon footprint measured by ‘embodied energy’ and ‘embodied carbon’, i.e., ‘CO2e emission’ of concrete

Analysis of Solar Refrigeration System Using Thermo Electric Cooling (Tec) Module

A refrigerator is a common house hold appliance that consists of a thermally insulated compartment and a heat pump that transfer heat from the inside of the refrigerator to its surrounding so that the inside of the refrigerator is cooled to a temperature below the ambient temperature of the room. Thermoelectric Cooling (TEC) solar refrigerator runs on energy provided by sun, which includes photovoltaic or solar thermal energy. Peltier Jean (1834) discovered the Thermoelectric (TE) property about two centuries ago;thermoelectric device havecommercialized during recent years. The applications of TE vary from small to large refrigerators. The Thermoelectric module refrigerator work on the principle of Peltier effect. Recently, the application of TEC modules in an industry is dramatically increased. Theyhave been adopting the solar refrigeration, widely recognized as alternative to the conventional vapourcompression system for their merits of energy saving and being eco-friendly. The paper presents a design of TEC solar refrigeration using thermoelectric cooling. The objective of this paper is to establish an alternative eco-friendly refrigeration cycle for producing a temperature usually encountered in a conventional refrigerator. By designing and manufacturing such type of refrigerator adds new dimension to the world of refrigeration. The proposed solar refrigeration system using TEC module is a feasible alternative for local refrigeration system. Briefly,the paper presents an economical and feasible model of solar refrigeration system