Special Binders Research Articles

Assembling of electrospun meshes into three-dimensional porous scaffolds for bone repair

Technical limitations of traditional electrospinning make it hard to produce three-dimensional (3D) scaffolds with hierarchical pore structures. Here, porous polycaprolactone (PCL) nanofiber meshes with different nano-hydroxyapatite (nHA) concentrations were prepared by electrospinning with stainless steel mesh as the collector, and 3D porous nanofiber scaffolds were fabricated via layer-by-layer assembly with a special binder (18% PCL/DCM solution). The single layer nanofiber mesh possessed very regular morphology with a hollow structure, and the nHA was not only embedded in the nanofiber but also exposed on the surfaces of the fiber, resulting in the improved surface chemical properties. The incorporation of nHA also had a significant effect on cell behaviours and functions. The 3D nanofiber scaffolds possessed hierarchical structures with interconnected micro and macro pores, which allowed cells to migrate between the adjacent layers, even throughout the scaffold. Cells filled the scaffold space and integrated with the nanofiber materials, forming scaffold/cells complexes in vitro. In addition, alendronate was successfully carried on the 3D composite scaffolds because of the high affinity of P–C–P backbone to calcium ions. The composite scaffolds treated with alendronate significantly promote the osteogenesis-related gene expression of human foetal osteoblasts. All these results suggest that 3D functional nanofiber scaffolds would be potentially useful for bone repair.

Mechanism of Immobilization of Toxic Elements in Special Binders

The paper deals with development of cementitious binders that would be able to efficiently immobilize toxic elements contained in various types of wastes. The basic component of the proposed binders are clinkers with phosphorus incorporated into the structure of clinker silicates, mixtures of cement with ash containing hydroxylapatite and belite-rich clinkers activated with sulfate anions. The prepared binders were mixed with water doped with various toxic elements; after a defined period of cement stone hydration the test beams were subjected to long-term testing of leachability of individual toxic elements. The research methods involved besides leaching tests also optical and electron microscopy.

Study of Surface Treatment of Freshly Fabricated Concrete Roof Tiles

This study deals with stability and quality of surface treatment of concrete roof tiles, considering the use of special inorganic binders spraying onto freshly prefabricated surface of concrete roof tiles. Their application leads to smoothing of surface defects generated from previous processing. Method of applying the coating is discussed in this work among with stability study of styrene-acrylate cement mixtures. Impact of presence of selected styrene-acrylate copolymer onto the hydration of cement is evaluated, in order to verify, for how long could be prepared mixture used for treating freshly fabricated surface of concrete roof tiles. Pull-off tests results after freeze-thaw test are further presented in this study to verify designed coating process properties.

Fabrication and Photocatalytic Degradation of TiO<sub>2</sub>/Porous Activated Carbon-Zeolite Composite Cylinder

Activated carbon, zeolite and titanium dioxide are wildly used for removing the organic compounds in waste water. Although, these materials exhibit high performance (in powder form), reclaiming of these materials from the waste water treatment system is still hard. The objective of this study is to fabricate hollow cylinder activated carbon-zeolite samples which were used as a porous substrate. Various ratios of activated carbon, zeolite NaA and clay were mixed with special binder to form dough before extruded to be hollow cylinder shape. The hollow cylinder samples were cut into 2.5 cm long and then were fired at 600 °C for 2 hours under 5%CO2+N2 atmosphere. The fired samples were dip-coated with TiO2-P25 and fired at 600 °C for 1 hour under 5%CO2+N2 atmosphere for testing the photocatalytic degradation of lignin solutions under UV light. The results showed that the strength of fired samples increasing with the ratio of clay increased. The XRD patterns of samples having clay addition showed peaks of zeolite and quartz. The physical properties, microstructure and photodegradation will be discussed.

Surface Treatment of Concrete Roof Tiles

Therein the application of special inorganic binders onto a freshly prefabricated surface of concrete roof tiles for the purpose of improving the quality of surface properties is reported. The possibilities of preparation of polymer-cement matrix with improvement gained from plasticizers are discused to obtain sprayable coating for roof tiles. Use of sprayable coating leads to smoothing of surface defects generated from previous processing of roof tiles thus improving the quality of surface leading to better durability of roof tiles with just a low increase of manufacturing cost.

RETRACTED: The biocorrosion of city sewer collector impregnated special polymer sulfur binder – Polymerized sulfur applied as the industrial waste material

RETRACTED: The biocorrosion of city sewer collector impregnated special polymer sulfur binder – Polymerized sulfur applied as the industrial waste material

A STUDY ON MARSHALL PROPERTIES FOR POLYMER MODIFIED BITUMEN IN DIFFFERENT MOLAR RATIOS

Polymer modified asphalt is increasingly used in road surfacing. Unmodified asphalt is sensitive to changes in temperature, it becomes brittle and cracks in cold weather and soften in high temperature, causing rutting and surface deformation. This research aims to prepare hot mix asphalt (HMA) for paving using polymer prepared from stearyl acrylate and methyl methacrylate and styrene in molar ratios: 0.5:0.5:0.2 and 0.5:0.5:0.5, respectively. The solid materials in the mix include normal and highly porous aggregates. 4,6,8% of two polymers by weight of asphalt were used to prepare special binders. The samples were tested for physical, chemical, ageing, SEM and TGA. The results revealed that the prepared hot mix asphalt (HMA) polymer had high performance as compared to ordinary one and the two polymer prepared could be used in road construction.

Engineering Cost–Benefit Analysis of Thin, Durable Asphalt Overlays

Use of sustainable and cost-effective pavement overlays as a rehabilitation technique has been emphasized for several years as oil prices continue their instability in the United States. Since the 1980s, significant advances have been introduced in asphalt pavements regarding material selection, mix design, and construction technology that improve pavement performance. Some of these improvements require the use of a highly modified asphalt binder and expensive high-quality aggregates to achieve the desired performance. This study developed four potentially cost-effective asphalt mixtures and efficient cross sections for asphalt wearing surfaces. The newly developed asphalt mixes incorporated locally available aggregates, special binder additives such as fibers, innovative surfacing technologies, or all of these techniques. The cost-effectiveness of the newly developed asphalt mixtures is presented, and the improved performance is considered. Deterministic and probabilistic life-cycle cost analysis was performed on the considered mixes. The performance of the considered mixes was investigated in the laboratory and on site under actual traffic. The engineering cost–benefit analysis showed that the new mixtures performed better and were more cost-effective than the control mixes considered.

Environmentally friendly road construction

Environmental pollution is a major problem in developing countries like Egypt. Reuse of waste polymers is considered an attractive solution for environmental white pollution and reducing of the costs of road pavement and maintenance. This research aims to prepare environmentally friendly hot mix asphalt (HMA) for paving using some industrial wastes as polypropylene and polyester fibers. The solid materials in the mix include normal and highly porous aggregates. 5% and 10% of waste polymers by weight of the asphalt were used to prepare special binders. The samples were tested for their physical properties, chemical properties, aging, scanning electron microscopy (SEM) and thermo-gravimetric analysis (TGA). The results revealed that the prepared HMA using 5% of waste polymer had high performance as compared to the ordinary one and the waste polymer could be used in road construction.

Chromatic and Rheological Characteristics of Clear Road Binders

Clear asphalt pavements provide specific functional characteristics to improve safety and climatic conditions in urban areas. The technological development of clear pavements refers to the formulation of special binders with particular chromatic characteristics. This research evaluated three clear binders with different chemical formulations with the aim of establishing the effectiveness of their mechanical properties and chromatic characteristics. Mechanical properties were analyzed by rheological methods. All clear binders were found to have specific dependence on stress levels, time, and temperatures. Different behaviors emerged, depending on the chemical origin of the binders. Chromatic characteristics were quantitatively evaluated by means of a digital image analysis. Red–green–blue as well as hue, saturation, and brightness models were used to determine and compare the chromatic performances of the three binders. The stability of the chromatic characteristics was also estimated with a laboratory aging process. Relationships were found between the chemical origin of the clear binder and its chromatic performance.

Hydroxyapatite powder used for rapid prototyping in medical engineering

A key requirement in the field of bone tissue engineering is the development of scaffold structures on which cells adhere. This can be done by fabricating scaffolds by direct procedures like Three-Dimensional (3D) printing or by indirect procedures like casting. With the 3D-printing process, different structures were built up using HydroxyApatite (HA) powder and a special binder material. Afterwards the printed 3D structures were sintered. For the casting process, moulds have been made of different resins by stereolithography and other processes using polymers and waxes. These structures were filled by a suspension of HA. The casting process yielded a better resolution than 3D printing, but exhibited restrictions with respect to the degree of porosity.

Effects of Dietary Binders on Survival and Growth Performance of Postlarval Tongue Sole, Cynoglossus semilaevis (Günther)

Abstract A 30‐d feeding experiment was conducted in tanks to investigate the effects of four different binders (2% in microdiet) on the survival, growth performance, and specific activity of digestive enzymes in tongue sole, Cynoglossus semilaevis Günther, postlarvae (24 d after hatching, with initial average wet weight of 22.4 ± 6.65 mg [mean ± SD]). Five approximately isonitrogenous and isoenergetic microbound diets were formulated with carrageenan (Car), sodium carboxymethylcellulose (CMS), sodium alginate (SA), and gelatin (Gel) as binders, and a diet with no special binder as a control. A commercial diet (RQ Com., manufactured by Marubeni Nisshin Feed Co., Ltd., Chita, Japan) was used as another tested diet, and Artemia nauplii was used as live prey control. The results showed that the survival of the fish fed SA diet (31.3%) was significantly higher than that of fish fed CMS (21.8%), Car (10.8%), and control (21.8%) diets (P < 0.05), but significantly lower than that of the fish fed the live prey (54.5%) diet (P < 0.05). The results of growth followed the similar pattern as that of survival, although there were no significant differences in specific growth rate (SGR) among fish fed SA, CMS, Gel, the control, and RQ diets (7.2, 6.8, 7.0, 6.9, and 7.3% per day; P > 0.05). However, fish fed Car diet had a significantly lower SGR (5.9% per day) than fish fed other diets. Percentages of secreted amylase in fish fed artificial diets were not significantly different, but fish fed artificial diets had significantly higher (P < 0.05) secreted amylase than live prey group. Percentage of secreted trypsin in fish fed SA diet (54.9%) was relatively higher compared with other binders, and not significantly different from RQ Com. and live prey treatments. However, trypsin in fish fed Car diets (29.3%) was significantly lower than in other groups. Specific activities of alkaline phosphatase (AP) in the intestine and AP and leucine aminopeptidase N in brush border membranes in fish fed SA diet (264.6, 1882.8, and 187.2 mU/mg protein) were relatively higher compared with other binders. These results indicate that SA is one of suitable binders compared with carrageenan, CMS, and gelatin in microdiet of postlarval tongue sole.

The role of calcium hydroxide in the formation of thaumasite

It has recently been derived by thermodynamic calculation that the presence or absence of calcium hydroxide plays a vital role in the resistance of cement paste or concrete against the formation of thaumasite. To obtain experimental data on this matter, special binders have been mixed and used for the preparation of mortar bars. These specimens were exposed to moderate sulphate attack for a period of 18 months at a temperature of 8 °C. Mortar bars containing calcium hydroxide showed visual signs of attack a few months after exposure, leading to expansion, mass loss and complete failure. In contrast to this, no signs of attack were observed when no calcium hydroxide was present in the microstructure. These results confirm the conclusions of earlier thermodynamic calculations that the presence of calcium hydroxide has an important impact on the formation of thaumasite. Calcium-rich C–S–H formed in the presence of calcium hydroxide is vulnerable against sulphate attack and the formation of thaumasite. In the absence of calcium hydroxide, C–S–H has a much lower calcium/silicon ratio and a higher resistance against the formation of thaumasite.

Production of special coal binders

Production of special coal binders

A Novel Coating Formulation for Silica Inkjet Layer Coatings

Silica based inkjet layer coatings made with the addition of special binders are widely used for inkjet coatings today. However, one limiting factor of the existing formulations is that they can only be used at low solids (<30%), which makes high speed coating very complicated. Another limiting factor is that most current formulations require the addition of special binders. However, the level of binder required is a compromise. Low levels of binders give good pigmented ink compatibility but poor physical properties. High volumes plasticize coating layer but reduce ink receptivity. This paper introduces a new nano structured silica coating formulation designed to overcome the limitations of existing inkjet technologies. The differentiating factors of this formulation are its high solids (up to 50%) and its self binding mechanism. Therefore, the ready-to-use formulation requires no organic binders. The rheology of the formulation gives very good runnability on various size presses and coaters. This new formulation has been proven in pilot and mill trials. Results showed high print density, dimensional stability, good water fastness and sharpness with most aqueous inkjet printers.

A RESEARCH ON RECYCLING TECHNOLOGY OF POROUS ASPHALT PAVEMENT THAT RAISED RECYCLING AGGREGATE MIXING RATE

Since the porous asphalt pavement which has drainage function has constructed for 20years. The time to repair the porous pavement will come soon at a burst. Therefore, it is necessary to establish the recycling technology for porous pavement in hurried. Also, the technology is desired to reuse milled pavement in large quantity at once. For the purpose that raising the rate of using recycled aggregates, we applied superheat steam crushing technology for manufacturing recycled aggregates, and could confirmed that mixing rate of recycled aggregates for the mixture up to 90% on our calculation. However, it is difficult to re-modify the old asphalt with sufficient quality for porous asphalt pavement if the large quantity of recycled aggregate put into the mixture. In order to solve this problem, special binder was developed to be re-modify the old asphalt in the range of 20% to 80% of mixing rate of recycled aggregate, and we confirmed that good recycled porous asphalt mixture is produced from this method.

New Generation Binders for Refractories and Ceramic Industries

In recent years, process changes that have taken place in refractories as well as ceramic industries call for use of materials which can sustain stringent conditions and provide increased life during use at minimum cost. Introduction of higher grade of special binders with the existing grade of raw materials may be a possible solution. Work has been carried out successfully to develop a number of binders, namely, calcium dialuminate cement, barium aluminate cement, magnesia based cement and develop applications of these binders along with siliceous sol, aluminium hydrate, etc. In this paper, an attempt has been made to detail out the characteristics of these new binders, improved properties obtained from the finished products after their application and finally the effect of the same in the performance.

Alkaline Activation of Kaolinitic Soils for the Production of Special Binders

The alkaline activation of Portland cement based materials, ground granulated blast furnace slag and pozzolans has been accomplished with success since the decade of 40, in several countries. The practicability of the use of the alkalis opens new opportunities for the production of special binders with properties different from those presented by the ordinary Portland cement. Besides the chemical composition, the mechanical strength of these alkali-activated materials depends a lot on the reactivity of the raw material, property that is influenced mainly by the specific surface area and crystalline degree of the raw material. Thus, an experimental program was carried out aiming at evaluating the influence of these variables in the compressive strength, at 3, 7 and 28 days of age, for mortars manufactured using alkaline activation of kaolinitic soils. The results have shown that the most suitable combination, in terms of mechanical strength and economy of energy, was the mortar manufactured with soil receiving a ½ hour grinding time and calcined at 650oC during four hours.

New Freeze‐Casting Technique for Ceramics with Sublimable Vehicles

A new ceramic freeze‐casting technique capable of manufacturing near room temperature with a sublimable vehicle was accomplished. Fluid‐concentrated slurries of Al2O3 powder in molten camphene (C10H16) were prepared at 55°C. These slurries were quickly solidified (frozen) at room temperature to yield rigid solid green bodies, followed by frozen camphene removal by sublimation (freeze‐drying) with negligible shrinkage. Sintering without any special binder burnout process yielded sintered bodies with over 98% theoretical density. The proposed advantages include (1) elimination of extremely cold temperatures, (2) elimination of troublesome binder burnout process, and (3) fast manufacturing cycle due to quick solidification.

Rutting and Moisture Resistance of Asphalt Mixtures Containing Polymer and Polyphosphoric Acid Modified Bitumen

ABSTRACTInitial engineering properties of materials as well as mechanical and environmental conditions governs the behaviour of asphalt pavements in service. To enable pavements to accommodate increasing traffic intensity and axle loads in varying climate environments, high quality bitumen is required. Special binders are also needed for other applications, such as bridges and airport runways. These examples suggest the necessity of bitumen modification. While modification of bitumen may be carried out via other methods, the most promising has been polymer modification This paper discusses the performance of high grade bituminous binders modified via synthetic polymers, polyphosphoric acid and combinations thereof, and their performance in asphalt mixtures in subsequent laboratory evaluation of moisture and mechanical damage (rutting). The effect of polyamine antistrip addition to asphalt mixtures modified with polymer and polyphosphoric acid is discussed.