This research aims to investigate the effect of the incorporation of sewage sludge as an activator in the formation of fly ash-based geopolymers. The geopolymer paste is made up of 15% sewage sludge by weight, with the remainder consisting of fly ash. The blended mix is activated using a hydroxide solution containing 10% Na2O relative to the total base material. To assess the mechanical and microstructural characteristics of the resulting geopolymer paste, it is necessary to conduct compressive strength tests as well as FESEM, SEM, XRD, and TG/DTA analyses. To evaluate the workability of the designed geopolymer paste, an area factor test can be used here. GPP4, using sodium silicate, achieved the highest 3-day compressive strength (38.0 MPa) with a dense, amorphous structure and minimal mass loss. In contrast, GPP3 with sludge showed a porous texture and moderate strength. TGA supports the observation of GPP4's amorphous nature, aligning with the findings from XRD and FESEM analyses. Further, sorptivity tests revealed changes in pore size and volume based on the activator and fly ash type. GPP4 also exhibited a thermal conductivity of 2.44×10⁻⁴ cal/cm/°C/s, demonstrating sludge's potential as an economical alternative for geopolymer binders.

Cow dung ash (CDA) is a waste material that is hazardous to health but often dumped in villages. However, CDA has pozzolanic properties that make it possible to be used in cement as a sustainable development practice, replacing some of the huge amount of CO2 generated worldwide in the production of Portland Cement (PC). In the present study mortars were prepared in which we substituted CDA for OPC by various proportions, and measured their strengths after 7 and 28 days of curing. After 7 days, the strongest mortar among the formulations tested was that with 10

Compressive strength is the most important metric of concrete quality. Various nondestructive and semi-destructive tests can be used to evaluate the compressive strength of concrete. In the present study, a new image-based machine learning method is used to predict concrete compressive strength, including evaluation of six different models. These include support-vector machine model and various deep convolutional neural network models, namely AlexNet, GoogleNet, VGG19, ResNet, and Inception-ResNet-V2. In the present investigation, cement mortar samples were prepared using each of the cement:sand ratios of 1:3, 1:4, and 1:5, and using the water:cement ratios of 0.35 and 0.55. Cement concrete was prepared using the cement:sand:coarse aggregate ratios of 1:5:10, 1:3:6, 1:2:4, 1:1.5:3 and 1:1:2, using the water:cement ratio of 0.5 for all samples. The samples were cut, and several images of the cut surfaces were captured at various zoom levels using a digital microscope. All samples were then tested destructively for compressive strength. The images and corresponding compressive strength were then used to train machine learning models to allow them to predict compressive strength based upon the image data. The Inception-ResNet-V2 models exhibited the best predictions of compressive strength among the models tested. Overall, the present findings validated the use of machine learning models as an efficient means of estimating cement mortar and concrete compressive strengths based on digital microscopic images, as an alternative nondestructive/semi-destructive test method that could be applied at relatively less expense.

Alkali-activated fly ash (AAFA) is desirable to be used in cement alternatives, but the resulting products differ considerably from cement products. Accordingly, new insights must be gained to predict their physicomechanical performance and to confirm the sustainability of such alternative products. Specific measurement schemes are needed to evaluate typical workability, strength, and durability characteristics. In the present work, we study two series of AAFA materials based primarily on the use of supplementary Ca 2+ ions and Si 4+ ions, in formulations using the waste products of seashell dust, sludge from the toothpaste industry, and silica fume, in addition to the fly ash. We study the effects of including supplementary trivalent and tetravalent ions, varying the alkali cations used, and varying the curing type upon the amorphousness, area factor, rate of strength gain, and long-term stability of the resulting AAFA product. We conduct maximum durability studies on AAFA under exposure conditions that are particularly aggressive for cement products but potentially appropriate for AAFA materials, using a novel experimental setup. AAFA usually performs better in such conditions because of its nonbiodegradable, amorphous nature, but AAFA is sometimes comprised of nanocrystalline gels, which can be thermally sensitive. Cyclic freezing and thawing of such AAFA products change the volume of the pore gel, leading to considerable fatigue within the pores and steady deterioration of the products. Accordingly, we study trends in amorphousness and crystallinity in representative AAFA products, to better predict their sustainable performance. The microstructural investigations include SEM, FESEM, TG, DTA, DSC, and EDAX analyses.

Purpose This paper aims to investigate the effect of delayed water curing on the mechanical and microstructural properties of fly ash-based geopolymer paste-blended with Ground Granulated Blast Furnace Slag (GGBS) with different rest periods. Design/methodology/approach The blended geopolymer paste was composed of GGBS (15 per cent of the total weight) and the base material, Fly Ash (FA). The blended mix was activated by activator solution (Sodium hydroxide and Sodium silicate) containing 6 per cent Na2O of total base material. The effect of delayed water curing has been studied by gradually increasing the aging period (Rest Period) from 2 hours to 24 hours in the formation of activated outcome along with Calcium Silicate Hydrate (CSH). To analyze the mechanical and microstructural properties of the resultant blended geopolymer paste, compressive strength test, FESEM and XRD have been carried out. Moreover, a long-term durability test subjected to sulphate exposure has been performed to evaluate the durability of the designed sustainable geopolymer paste. Findings The present paper shows that the delayed water curing incorporates secondary heat input enhancing the partial polymer formation along with CSH. Slag-blended AAFA-based geopolymer paste is seen to exhibit quick setting property. Also, AAFA-based geopolymer paste samples subjected to longer rest period show early strength gain at a high rate under water curing as compared to those subjected to the shorter rest period. Originality/value To the best of authors’ knowledge, the effect of delayed water curing on the mechanical and microstructural properties of slag-blended AAFA-based geopolymer paste has not been studied before.

This article represents that the mechanical and microstructural properties and durability of fly ash-based geopolymers blended with silica fume and borax are better than those of conventional fly ash-based geopolymers. Fly ash itself contains the sources of silica and alumina which are required for geopolymerisation. But a sufficient amount of high-reactive silica is able to rapidly initiate geopolymerisation with activation. Pure potassium hydroxide pellets and sodium silicate solution were used for preparation of alkaline activator solution. Fly ash geopolymer paste exhibited better mechanical properties in the presence of silica fume with slight portion of borax. The effect of silica fume-blended geopolymer paste on temperature fluctuation (heating and cooling cycle at certain temperatures) showed better performance than nonblended fly ash-based specimens. Durability property was evaluated by immersion of geopolymer specimens in 10% magnesium sulfate solution for a period of one year. The change in weight, strength, and microstructure was studied and compared. In the magnesium sulfate solution, a significant drop of strength to around 37.26% occurred after one year for nonblended fly ash-based specimens. It is evident that specimens prepared incorporating silica fume had the best performance in terms of their properties.

The present study aims to investigate the compressive strength and the underlying micro-structural change of fly ash geopolymer paste with silica fume and murram as supplements up to 10% and 2.5% of the total weight respectively.The workability property of the geopolymer paste samples was evaluated at a green state using a unique methodology based on the polar graph.Besides, various geopolymer paste samples were subjected to heat curing at different temperatures and also for different durations to find the influence of heat curing to the obtained compressive strengths.The present study also probed into the underlying micro-structural changes of the corresponding geopolymer paste samples through SEM (Scanning Electron Microscopy), MIP (Mercury Intrusion Porosimetry) and EDX (Energy Dispersive X-Ray Analysis).Through the present analysis, it can be concluded that blending of silica fume and murram with fly ash based geopolymer paste results in a sustainable high performance binder even at lower alkalinity with lower heat consumption as well as lower water content which can be considered as a better alternative of cement concrete binder to march towards environmental sustainability.

In this article, we look at the determinants of the new technology adoption by consumers in the case of mobile telecommunications. The dynamic nature of the telecom industry is a result of the frequent technological change. Consumers witness different technology standards in mobile communications, starting from the first generation (1G) to second generation (2G) subsequently to third (3G) and now experiencing fourth (4G) in some countries such as Norway, Sweden, South Korea, and the USA including ours. The movement from one standard to the other has been predicted to be smooth as all of them are vertical substitutes for each other. Given the various dimensions such as price, requirements, utility and so on, these technology standards are not perfect substitutes. The article investigates the prospect of a new technology standard roll out in India. A survey of 400 mobile phone customers in metro telecom circles has been carried out for this purpose. The study applies structural equation modeling (SEM) and explores the adoption intention of this new technology among the respondents. Results show that the presence of low-cost alternatives that is the availability of a lower technology standard poses a significant hurdle to the adoption of new technology services.

The logic for state monopoly of public utilities arises from increasing returns to scale and the concern that private business in these areas results in monopolistic exploitation of consumers. The state monopoly however is fraught with the danger of production inefficiency. In this backdrop, the market form of mixed oligopoly is contemplated in markets like health, education, electricity, gas, telecommunications etc, where public and private sector coexists. The private firms maximize profit but the public firm maximizes social welfare. Despite this theoretical exposition, it is often observed that public firms fail to make contributions according to their potentiality. The public firm in an industry with rapid change in technology can perform inefficiently due to decision making delay, adherence to social obligation. The policy makers must rise to these occasions then survival of public firms will be smooth. The option of public private partnership also derives affirmative results for the society and the particular industry per se.

This research has been executed to find various physical properties of alkali activated fly ash. Fly ash was used as base material for this research. KOH palates & Na2Sio3 solution were used as ingredients. The combination of KOH and Na2SiO3were used as alkali activator.The sample were mixed in a predetermine mix proportion. Compressive strength, water absorption and sorptivity has been carried out to investigate important physical properties of three different composites.

Freezing-thawing of various materials submerged in saline water was tested for one year. The experiment was done by a freezer where the individual specimen was submerged in 20% concentrated Magnesium Sulphate solution. It is already developed that fly ash geopolymer products show better strength and durability in compare to conventional cement product. This paper is further focused to the long-term durability of fly ash geopolymer with the incorporation of another postindustrial recycled material like blast furnace slag as supplement. The outcome of the research is that the drop of compressive strength on BGP (Blended Geopolymer) specimens are remarkably less compare to OGP (Ordinary Geopolymer) specimens. The important result was that alternative freezing and thawing did not affect much on strength of BGP specimens but had a considerable effect on strength of OGP specimens. Basically the reason for such a behavior is that the structure of OGP is unable to resist the tension caused by freezing of pore water due to volumetric increment. But for BGP the amount of water present in the pore is very less. Thus, more water confined inside the OGP causes cracking which allows more water absorption after every freezing – thawing cycle.

This study comprises the progress of alkali activated fly ash paste ensuing from altered fly ash classes. The exploration was carried out to check the strength and microstructure of series of specimens.Low calcium (Black and Grey) and high calcium (White) fly ash were used in the present research. The amalgamation of KOH and Na2SiO3 has been used as alkali activator. The simple aim of this paper is to study the progress of various physical properties along with change in pore morphology.FESEM were piloted to realize pore morphology and assess the reacted and unreacted areas of the trials.

This research represents the development of various physical properties of alkali activated fly ash (AAFA) prepared by various types of fly ash with different combination of alkali activators. Here three types of fly ash have been used as the base material of research experiment. Those are from Class F and Class C category respectively. The alkali activator has been prepared by the mixing of potassium hydroxide (KOH) and sodium silicate (Na2SiO3). This study shows how the combinational approach of different types of fly ash with varying quantity of alkali activator has affected the physical properties of AAFA. The properties which have been taken into considerations are compressive strength and water sorptivity. These properties have been broadly discussed in this paper too. A brief analysis of compressive strength with time variation has been discussed here.

Video segmentation acts as the fundamental step for various applications like, archiving, content based retrieval, copy detection and summarization of video data. Shot detection is first level of segmentation. In this work, a shot detection methodology is presented that evolves around a simple shot transition model based on the similarity of the frames with respect to a reference frame. Frames in an individual shot are very similar in terms of their visual content. Whenever a shot transition occurs a change in similarity values appears. For an abrupt transition, the rate of change is very high, while for gradual it is not so apparent. To overcome the effect of noise in similarity values, line is fit over a small window using a linear regression. Thus slope of this line exhibits the underlying pattern of transition. A novel algorithm for shot detection, hence, is developed based on the variation pattern of the similarity values of the frames with respect to a reference frame. First an algorithm is proposed, which is direct descendant of the underlying transition model and applies a threshold on the similarity values to detect the transitions. Then this algorithm is improved by utilizing the slope of linear approximation of variation in similarity values rather than the absolute values, following least square regression. Threshold on the slope is determined with a bias towards minimizing false rejection rate at the cost of false acceptance rate. Finally, a simple post-processing technique is adopted to reduce the false detection. Experiment is done with the video sequences taken from TRECVID 2001 database, action type movie video, recorded sports and news video. Comparison with few other systems indicates that the performance of the proposed scheme is quite satisfactory.

This research paper highlights the details of development of variousphysical properties of geopolymer with respect to time. Compressivestrength and sorptivity arethe most important physical properties which are broadly discussedbelow. Fly ash is the main constitute material of this Geopolymer. Sothis investigation here is basically based on the three types of thefly ash which is Class F (Black), Class F (Gray) and Class C (White)respectively. Apart from fly ash potassium hydroxide and sodiumsilicate are the two main constituents materials used here. Fly ashchanges in silicate modulus and in percentage of K2O have also made anobvious impact on it. Again the changes in compressive strength withtime variation graphs strongly focus on the above statement. So, thispaper represents the very changes in physical properties of geopolymerdue to the application of potassium hydroxide, changes in silicatemodulus and in percentage of K2O with respect to time.

Owing to its low initial cost, flexible pavements have been preferred in compare with rigid pavement. In the recent era, the insufficiency of raw materials and growing rates of bitumen are become a great problem. Now the benefits of rigid pavement is well recognized. But only disadvantage for concrete rigid pavement is the initial cost which is around 30% more than flexible pavement. For rigid pavement LCC (lifecycle cost) is much lesser than flexible pavement. Our industry is seeking for a true substitute which is sustainable and economic. In this study a typical nonconventional composite is developed by presenting Class C Flyash and Black cotton soil in alkaline medium. Flyash is an alumino-silicate material whether Black cotton soil is argillaceous and relatively reach in calcium carbonate (Kankar Nodules). The alkaline atmosphere insists the development of polymeric structure (Si-O-Al-O, tetrahedral structure) under hot steam curing. Clothjacketing has been used in the curing method of steam curing. Water glass sodium silicate solution has been used as alkali activator medium. Scanning Electron Microscopy, Compressive strength test, Ultrasonic Pulse velocity were conducted to evaluate its mechanical and microstructural characteristics.

This investigation explores the comparative studies of harden properties of typical fly ashes i.e. black, grey and white. This research shows that the parametric study of geo-polymer paste resulting from controlled percentage of alkali activator. The activator is prepared by mixing of Na2SiO3 and KOH solution. For every case activator subjected to a constant temperature 27°C stands for 24 hours. The geopolymer sample were mixed in a predetermine mix proportion. Then the sample were casted in a mould and it was cured for 24hours 85°C. To know the parameters like characteristic strength, water absorption, sorptivity the experiment was conducted.

In this program consequence of incorporating blast furnace slag on mechanical properties and durability of resulting fly ash geopolymer paste sample was investigated.The program consisted immersion of geopolymer samples having percentage blast furnace slag ranging from 10 to 20 of fly ash in a 10% magnesium sulfate solution up to a period of 15 weeks and evaluation of its resistance in terms visual appearance, change in weight and compressive strength at regular interval.Addition of blast furnace slag considerably improved mechanical properties and durability of geopolymers paste.

The aim of this research is to evaluate the curing temperature at which the fly ash based geopolymer can achieve its best mechanical properties with the presence of supplementary calcium source. Wide range of curing temperature from 55 o C-85 o C was imposed to sample GP (without any calcium compound) and sample GB (with 15% of slag as supplementary material) to have their comparative performance. The prime objective is to find out the right curing temperature in a manner to obtain the optimized strength under compression.