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"concrete additives"
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Smart cement : development, testing, modeling and real-time monitoring
\"Smart cement is a chemo-thermo-piezoresistive material that functions as a highly sensing 3-dimensional bulk sensor. It can be used for monitoring changes oflectrical resistivity in concrete by the addition of 0.03% of selected conductive or semi-conductive fibers are added to the bulk cement\"-- Provided by publisher.
BOOK
Handbook of alkali-activated cements, mortars and concretes
This book provides an updated state-of-the-art review on new developments in alkali-activation.The main binder of concrete, Portland cement, represents almost 80% of the total CO2 emissions of concrete which are about 6 to 7% of the Planet's total CO2 emissions.
eBook
Geopolymers and other alkali activated materials: why, how, and what?
This paper presents a review of alkali-activation technology, moving from the atomic scale and chemical reaction path modelling, towards macroscopic observables such as strength and durability of alkali-activated concretes. These properties and length scales are intrinsically interlinked, and so the chemistry of both low-calcium ('geopolymer') and high-calcium (blast furnace slag-derived) alkali-activated binders can be used as a starting point from which certain engineering properties may be discussed and explained. These types of materials differ in chemistry, binder properties, chemical structure and microstructure, and this leads to the specific material properties of each type of binder. The secondary binder products formed during alkali-activation (zeolites in low-Ca systems, mostly layered double hydroxides in alkali-activated slags) are of significant importance in determining the final properties of the materials, particularly in the context of durability. The production of highly durable concretes must remain the fundamental aim of research and development in the area of alkali-activation. However, to enable the term 'highly durable' to be defined in a satisfactory way, the underlying mechanisms of degradation--which are not always the same for alkali-activated binders as for Portland cement-based binders, and cannot always be tested in precisely the same ways--need to be further analysed and understood. The process of reviewing a topic such as this will inevitably raise just as many questions as answers, and it is the intention of this paper to present both, in appropriate context.[PUBLICATION ABSTRACT]
Journal Article
Nickel Remediation by Adsorption Technique Achieving the Concept of Zero Residue Level
Nickel is a major threat to the wastewater discharged from industries, where it is used, because it is classified as a carcinogenic heavy metal. Due to the need to treat polluted water with the highest efficiency and lowest cost, the promising adsorption technology using agricultural waste has proven to be an effective solution for treating water pollution with various pollutants. This study is concerned with determining the ability of a household waste to remove nickel from contaminated aqueous solutions by the adsorption method at different operating conditions. Waste tea leaves (WTL), which are discarded in huge quantities annually, showed noticeable nickel removal efficiency at more than 74% at acidity, shaking, concentration, time, temperature, and adsorption dose of 6, 350 rpm, 42 ppm, 120 min, 20°C, and 5.5 g, respectively. Although the adsorbent used had a low surface area of 12.251 m2/g, FTIR test before and after adsorption confirmed the presence of various functional groups capable of efficiently performing the adsorption function. Furthermore, FESEM test showed that the adsorption medium suffered significant changes compared to what it was before treatment with contaminated solutions. The use of toxic adsorption residues in a beneficial way was tested by adding them to concrete mixtures and studying the compressibility performance. The results showed that the additives increased the compressive strength of the concrete by more than double before it reached the failure point. Thus, this investigation confirmed the possibility of achieving the concept of zero residue level through waste management in an eco-friendly manner. Keywords: Adsorption, Concrete additives, Nickel, Waste tea leaves, Zero residue level.
Journal Article
Natural minerals mixture for enhancing concrete compressive strength
The construction material quality is required to be improved in order to enhancing structure stability, optimizing construction cost and quality. The kaolin and bentonite have been mixed in equal quantity and treated by heat for 1 hour under 600 oC, 800 oC and 1000 oC to create new minerals under high temperature condition to introduce an acceptable concrete additive for achieving concrete compressive strength in early age.To study micro properties of additive-cement mixture, X-ray and FESEM experiments have been used. The results indicate that acceptable proportion of unheated kaolin-bentonite is improving the concrete compressive response. But if kaolin-bentonite mixture treated by heat under 800 oC and in quantity of 12 % has been used in concrete mixed design, then the concrete compressive strength of 7 days shows the best result. The result is due to the development of new minerals under high temperature condition in mineral mixture and also kaolin-bentonite additive change cement past crystal and lead to enhancement of nano structural cement bonding.
Journal Article
Chemical admixtures for concrete
Chemical admixtures are used in concrete mixtures to produce particular engineering properties such as rapid hardening, water-proofing or resistance to cold. Chemical Admixtures for Concretesurveys recent developments in admixture technology, explaining the mechanisms by which admixtures produce their effects, the various types of admixtures available, their selection and use.Because of the economies they can offer, admixtures are being used increasingly in civil engineering projects worldwide. The book pays particular attention to good practice and includes a detailed chapter on the international standards currently in force.
eBook
Nonconventional Concrete Technologies
Nonconventional Concrete Technologies: Renewal of the Highway Infrastructure identifies research and development opportunities in innovative, nonconventional materials and processes that have the potential to accelerate the construction process, improve the durability of highway pavement and bridges, and enhance the serviceability and longevity of new construction under adverse conditions.
eBook
Sustainable heavy concrete additives: Evaluating granite-based solutions for eco-efficient construction
This article presents the results of a study on the influence of one component of a newly developed modifying additive (specifically, granite dust) on the strength properties of concrete. The comprehensive study included standardized tests of beam samples for flexural and compressive strength. The research was conducted with varying concentrations of granite in the concrete mix: 1%, 2%, 3%, and 4%. The study results yielded curves illustrating changes in concrete strength relative to the concentration of granite added to the mix. The resulting curve of this relationship indicated that the optimal concentration of granite in concrete is 2%, at which the maximum sample strength was observed. With further increases in granite concentration, a decrease in strength was noted, both in compressive and flexural strength indicators.
Journal Article
Science and Technology of Concrete Admixtures
Science and Technology of Concrete Admixtures presents admixtures from both a theoretical and practical point-of-view.The authors emphasize key concepts that can be used to better understand the working mechanisms of these products by presenting a concise overview on the fundamental behavior of Portland cement and hydraulic binders as well as.
eBook
Improving enzymatic hydrolysis efficiency of corncob residue through sodium sulfite pretreatment
The effects of sodium sulfite pretreatment on the delignification rate, cellulose content, enzymatic hydrolysis efficiency, and glucose yield of corncob residues (CCR) were investigated. The optimum pretreatment conditions were as follows: 12% sodium sulfite, with a pH value of 7, a temperature of 160 °C, and a holding time of 20 min. Under the optimal conditions, the cellulose content in the pretreated residue was 85.17%, and sodium lignosulfonate with a sulfonation degree of 0.677 mmol/g was obtained in the waste liquids. A delignification rate of 77.45% was also achieved after the pretreatment. Enzymatic hydrolysis of pretreated CCR was carried out with cellulase (5 FPU/g substrate) and β-glucosidase (10 IU/g substrate) for 48 h. The untreated CCR were hydrolyzed using cellulase (20 FPU/g substrate) and β-glucosidase (10 IU/g substrate) for 48 h. The comparison results showed that sodium sulfite pretreatment improved the enzymatic hydrolysis efficiency and glucose yield, which increased by 28.80% and 20.10%, respectively. These results indicated that despite the application of low cellulase dosage, high enzymatic hydrolysis efficiency substrate could be produced, and the sodium lignosulfonate which can be used for oilfields and concrete additives was obtained from the sodium sulfite–pretreated CCR.
Journal Article