Literature Review of Fal-G
CHAPTER. 2 Literature review GENERAL Fly ash is a waste product from thermal power plants where pulverized coal is used for the as per the literature review GouravHYPERLINK “http://biblioteca. universia. net/autor/Gourav,%20K. html”, Studies, 2007. Fly ash is being utilized in the blended cements, additive for concrete and manufacturing of concrete blocks and bricks. Fly ash-lime-gypsum bricks are being manufactured and marketed throughout the country.
The literature review on fly ash-lime-gypsum (FALG) mixtures as intended to manufacture bricks or blocks for masonry applications indicates several gaps in understanding the various aspects of the technology. The present thesis is an attempt to understand the behavior of compacted stabilized fly ash mixtures for the manufacture of fly ash bricks and characteristics of masonry using such bricks. A brief introduction to the technology of compacted stabilized fly ash bricks for structural masonry is provided.
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The main focus of the investigations is on arriving at the optimum stabilizer-fly ash mixtures considering density, stabilizer-fly ash ratio, curing conditions, etc. as the variables. Therefore the parameters/variables considered in the investigation include: (a) density of the compacted fly ash mixture, (b) stabilizer-fly ash ratio, (c) curing duration (normal curing and steam curing) and (d) dosage of additives like gypsum. The investigations clearly show the possibility of producing bricks of good quality using compacted fly ash-lime gypsum mixtures.
Wet compressive strengths of 8- 10 MPa was obtained for compacted fly ash-lime-gypsum bricks at the age of 28 days. Wet strength to dry strength ratio for these bricks is in the range of 0. 55 – 0. 67. Initial tangent modulus for the fly ash-lime-gypsum bricks in saturated condition is in the range of 8000 – 12000 MPa. There is a large scope for selecting optimum mix ratios of Fly ash, sand, lime and other additives to obtain a specific designed strength for the brick. The thesis ends highlighting major conclusions of the investigations.
A general study conducted on M30 strength of neat FaL-G has indicated that 1. 5 times of its dosage by weight, as against OPC, keeping the other aggregate same, renders a mortar or concrete of parallel grade strength. A Study on workability for M15 grade concrete has not shown any slump, unlike OPC. The additional 50% input of FaL-G cement might have rendered relatively better cohesion for wet concrete to show this phenomenon. Hence a different approach to study workability of FaL-G concrete has to be developed. Even at low workability, this can be considered as roller compacted concrete.
FaL-G can replace OPC in many avenues. The reinforcement behavioral studies in reinforced FaL-G cement concrete (RFCC) are in progress but the postulations indicate that the constituent of FaL-G being 1. 5 times more than OPC by weight which in other words 3 times by volume of account of two to one ratio in densities, the specific area of cement matrix is relatively larger in RFCC than in RCC. Thereby reinforcement is more closely coated with cementitious gels and more safely ensured for water impermeability to veto the chances of corrosion.
However FaL-G is weak abrasive product hence may be avoided on high abrasive prone areas, till its abrasive resistance is virtually improved. It is cheap in cost; transportation cost can be reduced by decentralizing the FaL-G cement activities. Fly ash-based brick and cement are far superior in engineering properties over their conventional competitors. This knowledge needs to be disseminated globally, more so in second and third world countries, through tangible technical explanations (Bhanumathidas and Kalidas 2003).
Although results of FaL-G bricks and hollow blocks were promising, and the technology could not be implemented due to initial consumer resistance in adapting to new materials. Ambalavanan and Roja (1996) in their study of FaL-G bricks utilized waste lime and gypsum with fly ash. They have observed that in most cases the use of waste lime does not give technically desired results and some improvement is needed to increase the strength of FaL-G bricks. The treatment to be given to waste lime increases the cost of FaL-G bricks significantly as compared to conventional bricks, which is hindering the commercialisation of this new material.
Some researchers have reported that there is fall in strength in FaL-G composites at later age. This aspect should be considered in the field application of FaL-G products. For wider application of FaL-G bricks and hollow blocks in the housing sector, extensive research is further needed. ENGINEERING & MECHANICAL PROPERTIES OF FAL-G Radhakrishnas (2010) preparation of FAL-g composite included both blocks & cubes, with different parameters like finesse of fly ash, aggregate to binder ratio, degree of saturation, age & testing the blocks and cubes for unconfined compression to determine the compressive strength.
The strength data was generalized for a reference value of water-to-FaL-G ratio. A phenomenological model was developed to account for synergy between the materials used. Its robustness was verified with an independent set of experimental data. The predicted strength values are in close agreement with the experimental strength. He reinforced the possibility of using the model in the field to re-proportion the FaL-G mix of any consistency.
Ismail Demur and Serhat Baspinar, 2007: investigated the effect of different type of pozzolan additions to cement free lightweight block made from fly ash–lime–gypsum mixture and observe the changes in physical, mechanical, thermal properties and microstructure Thermal conductivity of the fly ash–lime–gypsum mixture was improved by the addition of the expanded perlite. Optimal strength-thermal conductivity combination was obtained by the usage of silica fume and expanded perlite together. Improved strength properties were obtained by using hydrothermal curing conditions and super plasticizer addition.
Mingjie Hua et al, 2009: conducted test using- -new type of semi-rigid road sub-bases. , which is a mixture of FGD gypsum, water glass and slaked lime. They studied molded samples of this new material & investigated using different curing methods and measuring unconfined compressive Strength, soundness and water stability. Their team showed that the road sub-base material reflects excellent mechanical properties and soundness durability. S. K. Antiohos et al; 2007: In their test they studied Mechanical and durability characteristics of gypsum-free blended cements incorporating ulphate-rich reject fly ash. No gypsum was added in the mixtures, since it is believed that sulphate ions necessary for the prolongation of the setting process (commonly provided by gypsum) could be provided by fly ash enriched in sulphates. Their tests results revealed that waste materials not up to relevant standards could still contribute to the production of quality products of energy and economical efficiency. * This article is not included in your organization’s subscription. However, you may be able to access this article under your organization’s agreement with Elsevier.
As per Patent paper, Accession Number: 01022792; This paper presents the results of a laboratory investigation on tensile strength, bearing ratio, and slake durability characteristics of a class F fly ash stabilized with lime alone or in combination with gypsum. They developed Empirical models to estimate tensile strength, bearing ratio, and slake durability indices of stabilized fly ash from unconfined compressive strength test results are also proposed herein. They concluded with enhanced tensile strength and durability characteristics, the stabilized fly ash may find potential use in civil engineering construction.
Ambarish Ghosh; 2006: presents paper with results of a laboratory investigation on tensile strength, bearing ratio, and slake durability characteristics of a class F fly ash stabilized with lime alone or in combination with gypsum. Empirical models to estimate tensile strength, bearing ratio, and slake durability indices of stabilized fly ash from unconfined compressive strength test results are also studied, he reported that, with enhanced tensile strength and durability characteristics, the stabilized fly ash may find potential use in civil engineering construction.
D. P. Benz et al; (2010); presents paper about thermal Properties of High-Volume Fly Ash Mortars and Concretes. Paper focuses on a characterization of the thermal properties, namely specific heat capacity and thermal conductivity, of such mixture. Because the specimens being examined are well hydrated, estimates of the specific heat capacity based on a law of mixtures, with a “bound specific heat capacity value being employed for the water in the mixture, provide reasonable predictions of the measured performance.
Observed measured values should provide a useful database for evaluating the thermal performance of high volume fly ash concrete structures. RESEARCH PAPER 1999: points about the effects of processing and materials variations on mechanical properties of lightweight cement composites. The mechanical properties were improved by increasing the amount of silica fume, fly ash, and fibers. Paper says both carbon fibers and alkali-resistant glass fibers were effective in reinforcing the matrices, but carbon fibers were superior to glass fibers.
Fabrication techniques for producing lightweight cement composites that can substitute for autoclaved lightweight concrete was developed. Md. Moinul Islam1and Md. Saiful Islam 2010: did research about Strength Behaviors of Mortar Using Fly Ash as Partial Replacement of Cement. Concrete Research Letters Vol. 1(3) this paper reports the results of an experimental investigation carried out to study the effects of fly ash on strength development of mortar and the optimum use of fly ash in mortar.
His test results show that strength increases with the increase of fly ash up to an optimum value, beyond which, strength values start decreasing with further addition of fly ash. Among the six fly ash mortars, the optimum amount of cement replacement in mortar is about 40%, which provides 14%higher compressive strength and 8% higher tensile strength as compared to OPC mortar. Jia-sheng Chen1 et al; February 2010: His study results show that yellow phosphorus slag can be used as the cement substitute for potential coagulation property.
The hydration reaction involves hydration stage, solidifying stage, and strength stage with Ca (OH) 2 as the activating agent. The reaction rates of yellow phosphorus slag, Portland cement, and ultrafine powder hydration with the increase of microstructure stability and initial strength. S. Maitra et al; 2005: Effect of heat treatment on properties of steam cured fly ash-lime compacts was studied. Kinetics of thermal dehydration of the compacts was also studied from thermo gravimetric measurements under non-isothermal condition to ascertain the order of dehydration process and the associated activation energy.
Seema Karami1 et al; 2010: Research was undertaken to study the effect of sulphate activation of Run of Station Ash (ROSA) blend with Red-Gypsum (RG), Plaster Board Gypsum (PG) and By-Pass Dust (BPD). Research on Fly ash, Lime and Phospho gypsum (FaL-G) reported that when gypsum was added to Fa-L mix, the compressive strength increased by 3 and 22 times in comparison with that of Fa alone and Fa-L at 28 days curing time, respectively [A. Ghosh and Ch. Subbarao, 2001]. FaL-G is a hydraulic binder that was used for bricks and hollow blocks [Kumar, 2002].
Analysis of aerated concrete block wall; construction quality control; paper gives information about aerated cement concrete blocks are made of , lime, gypsum and fly ash, or river sand as the main raw material, aluminum is made by the gas-foaming agent, molding, maintenance and other craft made of autoclaved porous block walls material. As a load-bearing and non load-bearing structural materials and thermal insulation envelope materials, with a light weight, thermal insulation, sound insulation performance is good; there is a certain mechanical strength and process ability advantages.
This paper discusses the aerated concrete block wall construction quality control points. | ENVIRONMENTAL FACTORS PapitaSaha & ShyamalKSanyal;2010;The present contribution deals with the removal of cadmium ion using clay soil mixed with different admixture (cement, gypsum, lime, bentonite) as adsorbent in laboratory scale experiment. In continuous experiment it was observed that the % removal was 95–99%. A mathematical treatment of this adsorption phenomenon has been developed and it was observed that the experimental results showed satisfactory agreement with the theoretical predicted results. M.
Ahmaruzzaman; 2010: In this paper, the utilization of fly ash in construction, as a low-cost adsorbent for the removal of organic compounds, flue gas and metals, light weight aggregate, mine back fill, road sub-base, and zeolite synthesis is discussed. The adsorption capacity of fly ash may be increased after chemical and physical activation. Converting fly ash into zeolites not only alleviates the disposal problem but also converts a waste material into a marketable commodity. Investigations also revealed that the unburned carbon component in fly ash plays an important role in its adsorption capacity.
Future research in these areas is also discussed. | As per the experimental studies done by S. Geetha, & Ramamurthy; 2010: Chemical activation is done using Na2SO4 to enhance the strength of the cold-bonded aggregate by accelerating the pozzolanic reaction and formation of more ettringite. It was observed that increase in binder and Na2SO4 dosages increased the strength and decreased the open porosity thereby reducing the water absorption As per, Lal C. Ram & Reginald E. Masto; 2010: Studies the application of FA has improved the physical, chemical and biological qualities of soil to which it is applied.
FA generated in India tends to be mostly alkaline, with lower levels of trace elements than are often found in FAs from other countries. The concentrations of potential chemical stressors, predominantly metals, in Indian FAs are often less than established or proposed permissible limits and are thus better suited for soil application. A major logistic limitation to the use of FA could be the cost involved in transport of ash from production to utilization sites. High Volume Fly Ash Concrete and Its Mechanism Posted: 2009- It is known that the fly ash emissions from industrial by-products are very large.
To fully exploit the potential activity of industrial waste, fly ash has to be used to reduce the amount of cement concrete. To reduce the Cost of production; turning waste into treasure, of harm into, saving a lot of valuable land dumping of fly ash; a greater degree of high performance edge, to improve concrete workability, durability, and physical and mechanical properties we have to use Fly Ash Concrete In one embodiment the invention provides solid bricks produced by compressing together fly ash, bottom ash, gypsum, calcium carbonate, and lime.
These bricks have sufficient structural strength for use in building and construction. In another embodiment, waste materials are encapsulated in a mixture of fly ash, bottom ash, gypsum, lime, and calcium carbonate and compressed into bricks that may be disposed of in an environmentally acceptable manner. Further, the compressed bricks containing waste material may be coated with an impermeable membrane of a synthetic polymeric material. Further, the invention provides a mobile, trailer-mounted apparatus for compressing the mixtures into bricks.
Mohammad M. Khabiri; 2010: studied the effect of Stabilized Sub base, Containing Waste Construction Materials on Reduction of Pavement Rutting Depth, & examined the changes of rutting depths due to using from stabilized Recyclables materials. Milken et al; study & investigates the feasibility of using coal fly ash and fly ash-bentonite mixtures as a barrier material for mine waste. Tara Sen and Umesh Mishra; 2010: studied, applications of industrial wastes considered in road construction with great interest in many industrialized and developing countries.
The results of this study suggest that the addition of 10% bentonite to coal fly ash reduced the hydraulic conductivity of the coal fly ash to less than 1_10? 9 ms and improved the chemical compatibility for mine waste containment. Use of these materials in road making is based on technical, economic, and ecological criteria. Various Industrial wastes for use in the construction of highway have been found to be successful. ECO-FRIENDLY BUILDING MATERIALS AND TECHNOLOGIES. Eco-housing Assessment Criteria – 2009. Information about Fly Ash Lime Gypsum Brick.
Fly ash-lime-gypsum bricks / blocks are very good products, giving the highest strength among various bricks. These require relatively higher investment and expensive raw materials to give arrange of high strength products. This is most suitable for mechanized operations, though semi mechanized operations are also possible. Fly ash lime gypsum bricks are made up of 60% fly ash, 10-20% lime and 10-20% gypsum. These bricks have medium range strength. Minimum compressive strength (28 days) of 70 kg/cm2 can easily be achieved and this can go up to 250 Kg/cm2 (in autoclaved type).
Advantage of these bricks over burnt clay bricks: Lower requirement of mortar in construction, Plastering over brick can be avoided, Controlled dimensions, edges, smooth and fine finish & can be in different colors using pigments and cost effective, energy-efficient & environment friendly (This avoids the use of fertile clay). Polycor Vetrazzo; -2010: did research about recycled material & investigates the composition preferably used for recycle that is Fal-g and observes, has high recycle content.
The sheet-form material made in accordance with the invention can be used to provide exposed solid surfaces, for example, surfaces for shower walls and floors, counter-tops, table-tops, and the like, where low hydraulic permeability and high compressive and tensile strength are required. The cement content is relatively low, preferably in the range of about 3% to 20% by weight, and the pozzolan to cement ratio is relatively high, preferably equal to or greater than unity and can be suitably used as alternative construction material.
Godfrey MadzivireLeslie et al; 2010: studies about Balfo Application of coal fly ash to circumneutral mine waters for the removal of sulphates as gypsum and ettringite. They observed Subsequent treatment of circumneutral mine water to pH greater than 11 resulted in more than 60% sulphate removal. Treatment of circumneutral mine water to pH greater than 11 with FA followed by seeding with gypsum crystals and the addition of amorphous Al(OH) 3 resulted in removal of sulphate to levels below the Department of Water Affairs and Forestry (DWAF) water quality effluent limit (500 ppm0). Keat-Teong LeeKok-Chong Tan, et al, 2007, they devised a
Model that was found useful to predict the daily operation of flue gas desulfurization processes by using CaO/CaSO4/coal fly ash sorbent to remove O2from flue gas. Puvvadi V et al; 2010: studied about Gypsum treated fly ash as a liner for waste disposal facilities. They investigated the use of gypsum, which is known to accelerate the unconfined compressive strength by increasing the lime reactivity, and further improving the hydraulic conductivity. They made an attempt in the present context to reduce the hydraulic conductivity by adding lime content up to 10% to two selected samples of class F fly ashes.
They investigated that the higher amount of lime in the presence of sulphate is observed to produce more cementitious compounds which block the pores in the fly ash. The consequent reduction in the hydraulic conductivity of fly ash would be beneficial in reducing the leach ability of trace elements present in the fly ash when used as a base liner. J. Sanjurjo Sanchez et al. 2010. Studied about the deposition of particles on gypsum-rich coatings of historic buildings in urban and rural environments and made comparisons.
They studied XRF and SEM analyses of these coatings and their comparison with both the composition of dust coatings formed by the deposition of gaseous and particulate matter in an urban and a rural locality allows assessing which pollution sources are the most damaging for these materials, knowing the elemental composition of these emissions. Aly Ahmed et al; 2011: did Investigations of using recycled gypsum “bassanite” which is derived from gypsum waste plasterboard and waste plastic trays for ground improvement; this can be also used for soil improvement.
Recycled gypsum content, curing time and frost heave property throughout capillary rise test were investigated to determine the behavior of treated soil with recycled gypsum. In addition, size, content and aspect ratio of strips of waste plastic trays were investigated. Adding strips of waste plastic trays to samples treated with recycled gypsum enhanced both splitting tensile and compressive strengths as well increased the value of secant modulus. The size and content of strips of waste plastic trays have significant effect on the potential of capillary rise and the enhancement of strength and stiffness of tested soil.
Mridul Garg et al; 2010:did investigations about environment hazard mitigation of wasteHYPERLINK “http://www. sciencedirect. com/science? _ob=ArticleURL&_udi=B6V2G-50HWJ3X-9&_user=10&_coverDate=07%2F14%2F2010&_alid=1529465624&_rdoc=2&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=5702&_sort=r&_st=13&_docanchor=&view=c&_ct=15&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=227eba22bc38c03d62ab580849bcc1c7&searchtype=a” gypsumHYPERLINK “http://www. sciencedirect. om/science? _ob=ArticleURL&_udi=B6V2G-50HWJ3X-9&_user=10&_coverDate=07%2F14%2F2010&_alid=1529465624&_rdoc=2&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=5702&_sort=r&_st=13&_docanchor=&view=c&_ct=15&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=227eba22bc38c03d62ab580849bcc1c7&searchtype=a” and chalk& how to utilize HYPERLINK “http://www. sciencedirect. com/science? _ob=ArticleURL&_udi=B6V2G-50HWJ3X-9&_user=10&_coverDate=07%2F14%2F2010&_alid=1529465624&_rdo =2&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=5702&_sort=r&_st=13&_docanchor=&view=c&_ct=15&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=227eba22bc38c03d62ab580849bcc1c7&searchtype=a” in construction materials. The paper deals with studies on select wastes like phosphogypsum and chalk for use in value-added building materials. The engineering properties and techno-economics of materials like gypsum plasters, cementitious binders, boards/blocks, masonry cement and flooring tiles produced from phosphogypsum and lime have been detailed.
They came to the conclusion that the production and use of building materials from such wastes will protect the environment from degradation. The disposal and use of solid industrial wastes like phosphogypsum, fluorogypsum, fly ash, and slag can be met successfully. Activation or strengthening of fly ash-lime with gypsum Yang MinQian Jueshi and Pang Ying; 2007:studied about the Activation of fly ash–lime systems using calcined phosphor gypsum & also experiments were performed to determine the effect of calcined phosphogypsum on the strength of fly ash–lime binders.
Significant strength increases compared to binders without calcined phosphogypsum were observed due to the activation. They opined lime sludge, is significant in view of their availability and potential applications. Kelly RuschTingzong Guo and Roger; 2002: They investigated how best PG can be stabilized with class C fly ash and lime for potential use in marine environments. Development of the ruptures in the composites must be considered when the composites are used for aquatic applications.
They came to the conclusion that effective diffusion coefficients and effective diffusion depths alone are not necessarily good indicators of the long-term survivability of PG: class C fly ash: lime composites. Larbi Kacimi & Martin Cyrand Pierre Clastres; 2010: The objective of this study was the synthesis of ?? L-C2S (Ca2SiO4) belite cement, starting from fly-ash of system CaO–SiO2–Al2O3–SO3, and using the hydrothermal method in alkaline solution. The optimization of the synthesis parameters (temperature and time of stirring, pH of solution, temperature and duration of mixture burning) was also studied.
The results obtained showed that these ashes could form belite cement composed of only one dicalcium silicate phase (?? L-C2S). Bhanumathidas and Kalidas; 2004: They studied the Point of View Dual role of gypsum: Set retarder and strength accelerator. They opined while all fly ashes may not need additional gypsum, care has to be taken not to deprive those fly ashes in need of additional gypsum FaL-G technology, developed by the authors, achieved its breakthrough by tapping the potential of calcium aluminates towards the formation of ettringite and mono-sulphate; thus changing the pace of lime-fly ash chemistry.
They said gypsum plays a predominant role as the strength accelerator in the context of hydrated mineralogy in FaL-G. Moreover, gypsum works as set-accelerator in lime-pozzolana binders in contrast to its role as set-retarder in OPC. Stefania Grzeszczyk, and Katarzyna Front; 2000. They carried out rheological studies out on the effect of a super plasticizer from the sulphonated melamine formaldehyde (SMF) group upon the properties of fly ash suspensions containing a small quantity of mineral admixtures such as cement, lime and gypsum. Ghosh, et al; 2007: They studied about Leaching of Lime from Fly Ash Stabilized with Lime and Gypsum.
They presented leaching test results of a class F low lime fly ash stabilized with varying percentages of lime (4, 6, and 10%) alone or in combination with gypsum (0. 5 and 1. 0%).. The effects of factors like lime content, gypsum content, curing period, and flow period on leaching of lime from a compacted stabilized fly ash matrix are reported herein. Two non dimensional parameters, alpha sub coi and beta sub coi, are presented herein to study the effect of gypsum on the total amount of calcium leached out from the compacted stabilized fly ash.
They presented a model is also to estimate the amount of calcium leached out from the stabilized fly ash. Ambarish Ghosh 2010; conducted lab test to determine the compaction Characteristics and Bearing Ratio of Pond Ash Stabilized with Lime and Phosphogypsum. This paper presents the laboratory test results of a Class F pond ash alone and stabilized with varying percentages of lime (4, 6, and 10%) and PG (0. 5, and 1. 0), to study the suitability of stabilized pond ash for road base and sub base construction. As per the empirical model he developed to estimate the bearing ratio for the stabilized mixes through multiple regression analysis.
Linear empirical relationship has been presented herein to estimate soaked bearing ratio from unsoaked bearing ratio of stabilized pond ash. He concluded from the experimental results that pond ash-lime-PG mixes have potential for applications as road base and sub base materials. As per,PeijiangHYPERLINK “http://scitation. aip. org/vsearch/servlet/VerityServlet? KEY=ASCERL&possible1=Sun%2C+Peijiang&possible1zone=author&maxdisp=25&smode=strresults&aqs=true” Sun and HwaiHYPERLINK “http://scitation. aip. org/vsearch/servlet/VerityServlet?
KEY=ASCERL&possible1=Wu%2C+Hwai-Chung&possible1zone=author&maxdisp=25&smode=strresults&aqs=true”-Chung Wu 2009, Splitting Tensile Strength of Fly Ash Activated by Hydrothermal Hot-Pressing Process, an innovative process of recycling fly ash (both Class F and Class C) into potential construction materials with superior mechanical properties is investigated. Several key parameters—such as treatment temperature, duration of process, and amount of chemical activator—are evaluated critically. The results confirm that fly ash can be solidified and specimens show splitting tensile strengths of about 1. 0 MPa by hydrothermal hot pressing alone.
With a small amount of chemical activator (NaOH), the tensile strength can reach as highas5. 4 MPa. Fal-g used as Road sub base parameters Weiguo ShenMingkai Zhoua and Qinglin Zhao; 2006:, Studied on lime–fly ash–phosphogypsum, FaL-g Binder. As per his their study a new type of lime–fly ash–phosphogypsum binder was prepared. To improve the performances of lime–fly ash binder this was a typical semi-rigid road base Material binder in China. They concluded the modified lime powder had much higher activity than ordinary quick lime or slaked lime powder; it was the best alkali activator to prepare lime–fly ash–phosphogypsum binder.
As per, Degirmenci & Nurhayat; 2008, they investigated Utilization of phosphogypsum as raw and calcined material in manufacturing of building products. The main objective of this research was to investigate the utilization potential of phosphogypsum with fly ash and lime in construction industry. On the basis of the test results, it was concluded that the curing conditions have an important influence on the compressive and flexural strength of the binder specimens. It was also concluded that the, Cementitous binder obtained can be used for the production of interior wall materials such as bricks and blocks
MinYang et al; 2008: presented a (Technical Note) regarding activation of fly ash-lime systems using calcined phosphogypsum. Experiments were performed to determine the effect of calcined phosphogypsum on the strength of fly ash lime binders. But lowering the lime to calcined phosphogypsum ratio of blends with the same fly ash content yielded a relatively lower compressive development at late ages. Strengths of samples cured first at 45[degrees] C in over 90% R. H. for 12 h and then at room temperature were better than those cured at room temperature all the time.
X-ray analysis suggests that the activation of calcined phosphogypsum to the systems was due to the formation of ettringite and dehydrate calcium sulfate during the hydration process. LJMU 2008 ANNUAL INTERNATIONAL CONFERENCE 20TH -21ST FEBRUARY 2008, LIVERPOOL, UK. This paper will review the various applications for coal fly ash associated with road construction, summaries the technical benefits and discuss in detail the environmental and sustainability considerations of its use. Composite masonry material from Fal-G A Paki Turgut; 2010: investigated about Masonry composite material made of limestone powder and fly ash.
LP waste and class-C FA were used to produce a composite material without the addition of Portland cement. They concluded, from Preliminary results obtained from the tests that masonry composites can be produced using LP, FA and water. | | | etd AT Indian Institute of Science ; 1994:Did investigation about-| -a method of using waste materials produced by coal combustion to produce useful products. In one embodiment the invention provides solid bricks produced by compressing together fly ash, bottom ash, gypsum, calcium carbonate, and lime.
These bricks have sufficient structural strength for use in building and construction. In another embodiment, waste materials are encapsulated in a mixture of fly ash, bottom ash, gypsum, lime, and calcium carbonate and compressed into bricks that may be disposed of in an environmentally acceptable manner. Further, the compressed bricks containing waste material may be coated with an impermeable membrane of a synthetic polymeric material. Further, the invention provides a mobile, trailer-mounted apparatus for compressing the mixtures into bricks. P.
Chindaprasirt; 2008: did investigation about Lightweight bricks made of diatomaceous earth, lime and gypsum. They studied Water content, pre-curing period, lime content, gypsum content and calcined temperature. The nature of hydration products and morphological characteristics of the lightweight bricks are also investigated. Yang et al; 2009 conducted studies about Preparation of load-bearing building materials from autoclaved phosphogypsum. The present study was focused on autoclaved PG and its use in making load-bearing wall bricks. Tobermorite was the significant hydrated product, which contributed to the strength of bricks.
The use of autoclaved PG for making load-bearing wall bricks was recommended instead of conventional burnt clay bricks. A possibility to get water-stable materials at curing in the ambient air. It was shown that water uptake might be reduced by different methods, the best of which is short-term impregnation by a hydrophobic liquid of the siloxane group. Results from experiments with small specimens and full size pressed blocks were compared. It is noted that blocks answered to the requirements of Israeli Standard to cement concrete blocks. As per the S. Marinkovic and A. Kostic-Pulek; 2007.
Examination of the system fly ash–lime–calcined gypsum–water. The feasibility of the utilization of the system fly ash–lime–calcined gypsum (? -hemihydrates)–water (the mass ratio 2:1:2:2. 5) for the production of building ceramics was investigated. S. Marinkovic and A. Kostic-Pulek opined curing of these products, a compressive strength of 4. 01 MPa in the water-cured and 7. 83 MPa in air-cured system developed. When the air-cured system was exposed to three alternate heating–cooling or three alternate cooling–heating cycles, the compressive strength increased (from 7. 83 to 9. 47 and 10. 55 MPa, respectively).
The fly ash–lime–calcined gypsum–water systems prepared in this work can be applied for the manufacture of products for internal walls (bricks and blocks). As per Vimal Chandra Pandey & Nandita Singh; 2010, systems Studies revealed that the lower FA incorporation in soil modifies the physico-chemical, biological and nutritional quality of the soil. He concluded that FA could be effectively used in the barren or sterile soil for improving quality and enhancing fertility. The purpose of this paper is to explore the possibility of FA addition into degraded soils for improving nutritional and physico-chemical properties.
As per literature review of Gourav, K 2010; fly ash-lime-gypsum (FALG) mixtures as intended to manufacture bricks or blocks for masonry applications indicates several gaps in understanding the various aspects of the technology. The literature review on the present thesis is an attempt to understand the behavior of compacted stabilized fly ash mixtures for the manufacture of fly ash bricks and characteristics of masonry using such bricks. A brief introduction to the technology of compacted stabilised fly ash bricks for structural masonry is provided.
Review of the literature on fly ash-lime and fly ash-lime-gypsum mixtures, and fly ash bricks are provided in chapter 1The main focus of the investigations is on arriving at the optimum stabilizer-fly ash mixtures considering density, stabilizer-fly ash ratio, curing conditions, etc. as the variables. Some of the major conclusions of the investigations are (a) compressive strength of compacted stabilised fly ash mixtures is sensitive to dry density of the specimens and the strength increases with increase in density irrespective of stabilizer content and type of curing, (b) Optimum lime fly ash ratio yielding maximum strength is 0. 5, (c) addition of gypsum accelerates rate of strength gain for compacted fly ash-lime mixtures (d) for 28 days wet burlap curing optimum gypsum content yielding maximum strength is 2% and maximum compressive strength is achieved for lime contents in the range of 10 – 17%, (e) steam curing (at 80 °C for 24 hours) gives highest compressive strength for compacted fly ash-lime mixtures. Compressive strength, flexure bond strength and stress strain relationship for the fly ash brick masonry using cement-lime mortars were evaluated.
The investigations clearly show the possibility of producing bricks of good quality using compacted fly ash-lime gypsum mixtures. Wet compressive strengths of 8- 10 MPa was obtained for compacted fly ash-lime-gypsum bricks at the age of 28 days. Wet strength to dry strength ratio for these bricks is in the range of 0. 55 – 0. 67. There is a large scope for selecting optimum mix ratios of fly ash, sand, lime and other additives to obtain a specific designed strength for the brick. Curing effect; on improving strength of fal-g.
As per, Is? k Yilmaz and Berrin Civelekoglu; 2009, this paper deals with the performance of the gypsum as an additive for treatment of the expansive clay soils by means of swell potential and strength. Gypsum can be used as a stabilizing agent for expansive clay soils, effectively. The literature contains a vast number of stabilizing techniques such as lime, cement, and fly-ash for treatment of expansive clay soils. They however concluded the use of gypsum as a stabilizing agent is currently not clear. As per Pimraksa and P.
Chindaprasirt; 2008, Water content, pre-curing period, lime content, gypsum content and calcined temperature are the factors investigated. The nature of hydration products and morphological characteristics of the lightweight bricks are also investigated. He concluded that the diatomaceous earth possesses pozzolanic property and can be used for making lightweight bricks. Concrete blocks of fal-g As per the literature review of Sunil Kumar. 2007, The compressive strength, water absorption and weight of FaL-G hollow blocks were determined .
FaL-G hollow blocks are light in weight and being hollow, impart thermal insulation to the buildings. In this paper, a study based on the results of an experimental investigation on FaL-G hollow blocks is presented. The durability of these blocks in terms of loss in compressive strength in sulfate environments is also presented in this paper. It is observed that FaL-G hollow blocks have sufficient strength for their use in general building construction.
High Volume Fly Ash Concrete and Its Mechanism Posted: 2009: As the fly ash emissions from industrial by-products is very large, large volume fly ash concrete to fully exploit the potential activity of industrial waste fly ash to reduce the amount of cement, concrete to reduce the Cost of production; to improve concrete workability, durability, and physical and mechanical properties. High Volume Fly Ash Concrete to save both cement, but also consume a large amount of fly ash, for the reduction of Environmental load of very effective.
High Volume Fly Ash Concrete as a new type of material has its own unique advantages, with its performance study, large volume fly ash concrete and continuously improves the performance. In one embodiment the invention provides solid bricks produced by compressing together fly ash, bottom ash, gypsum, calcium carbonate, and lime. These bricks have sufficient structural strength for use in building and construction. In another embodiment, waste materials are encapsulated in a mixture of fly ash, bottom ash, gypsum, lime, and calcium carbonate and compressed into bricks that may be disposed of in an environmentally acceptable manner.
Further, the compressed bricks containing waste material may be coated with an impermeable membrane of a synthetic polymeric material. Further, the invention provides a mobile, trailer-mounted apparatus for compressing the mixtures into bricks. As per the Technical paper ECO-FRIENDLY BUILDING MATERIALS AND TECHNOLOGIES. 2009. Fly ash-lime-gypsum bricks / blocks are very good products, giving the highest strength among various bricks. These require relatively higher investment and expensive raw materials to give arrange of high strength products.
This is most suitable for mechanized operations, though semi mechanized operations are also possible. Fly ash lime gypsum bricks are made up of 60% fly ash, 10-20% lime and 10-20% gypsum. These bricks have medium range strength. Minimum compressive strength (28 days) of 70 kg/cm2 can easily be achieved and this can go up to 250 Kg/cm2 (in autoclaved type). Advantage of these bricks over burnt clay bricks: Lower requirement of mortar in construction, Plastering over brick can be avoided, Controlled dimensions, edges, smooth and fine finish & can be in different colors using pigments and cost effective, energy-efficient & environment friendly