Fine Glass Powder Research Articles

Strength Development Characteristics of Concrete Replaced with Different Waste Glasses from Display Industry as a Cementitious Material

In this study, the fundamental and mineralogical properties of the binary system incorporating the industrial display byproducts, liquid crystal display (LCD) and organic light emitting diodes (OLED), as a cementitious material. A substitution level of the fine glass powders, and water to binder ratio were kept at 30% and 0.4 for all mixes, respectively. Strength development for the blended concretes was monitored until 91 days of curing, during which a modification of pore distribution was examined by mercury intrusion porosimetry. Simultaneously, the pozzolanic activity was evaluated by the content of calcium hydroxide (CH) in the cement pastes obtained from results of thermogravimetry analysis, and the phase composition of the specimens was quantitatively determined X-ray diffraction with Rietveld refinement method. As a result, the CH content in the glass-mixed specimen was decreased with time after certain age depending on glass types. Also, OLED was much effective to the pozzolanic activity, producing a higher content of C-S-H gel at 91 days, compared to LCD. This phenomenon may be attributed to a difference of Al2O3 and SiO2 content in the oxide composition, which would induce a shift of larger pore to micropore resulting in an increase in the strength for OLED concrete.

Direct Ink Writing Glass: A Preliminary Step for Optical Application.

In this paper, we present a preliminary study and conceptual idea concerning 3D printing water-sensitive glass, using a borosilicate glass with high alkali and alkaline oxide contents as an example in direct ink writing. The investigated material was prepared in the form of a glass frit, which was further ground in order to obtain a fine powder of desired particle size distribution. In a following step, inks were prepared by mixing the fine glass powder with Pluoronic F-127 hydrogel. The acquired pastes were rheologically characterized and printed using a Robocasting device. Differential scanning calorimetry (DSC) experiments were performed for base materials and the obtained green bodies. After sintering, scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses were carried out in order to examine microstructure and the eventual presence of crystalline phase inclusions. The results confirmed that the as obtained inks exhibit stable rheological properties despite the propensity of glass to undergo hydrolysis and could be adjusted to desirable values for 3D printing. No additional phase was observed, supporting the suitability of the designed technology for the production of water sensitive glass inks. SEM micrographs of the sintered samples revealed the presence of closed porosity, which may be the main reason of light scattering.

Experimental Investigation on Partially Replacement of Cement and Fine Aggregate by Glass Powder and Vermiculite

Concrete is the most widely used manmade material in the construction industry. So, it is essential to utilize industrial by - products and waste products instead of concrete, which has many advantages. Waste glass from glass manufacturing industries can be grounded and used as an alternative for cement. Glass has high silica content, thus making it potentially pozzolanic. Finely ground glass does not contribute much to alkali - silica reaction, which can be prevented by adding mineral admixtures. Vermiculite is a low density material obtained by exfoliating rock. It can be used as replacement for fine aggregate because of it’s specific properties such as light weight, improved workability, fire resistance. This project work aims at studying the effects of replacing cement and fine aggregate by glass powder and vermiculite respectively in M35 grade concrete. Vermiculite is added in 12 %, 15 % and 18 % of fine aggregate and glass powder is added in 15 %, 18 % and 20 % of cement. The main objective is to analyse compression, splitting tensile and flexural strengths for various proportions of vermiculite and glass powder are compared with conventional specimens.

Micro-chemo-mechanical features of ultra-high performance glass concrete (UHPGC)

The development of Ultra-High Performance Concrete (UHPC) opened new research directions for enhancing the architectural design, sustainability and serviceability of concrete structures. However, the costs and resource intensiveness trigger the need for innovative UHPC mix design incorporating alternative materials, such as post-consumption Glass Powder (GP). This works aims at disclosing the microstructure features of UHPGC, in which the constituents can be partially replaced by different fineness of GP without impacting the long-term strengths. By using the latest NI-QEDS technique (coupling NanoIndentation and Quantitative Energy-Dispersive Spectroscopy), as well as image analysis applied to EDS chemical mappings, it was possible to investigate mechanical properties of the microstructure constituents and their volume fractions. A conventional UHPC microstructure was compared to a similar system with 30% replacement of cement by GP and to another system with 50% replacement of silica fume by Fine GP (FGP). The results showed the key role of GP anhydrous particles contributing to the rigid skeleton of anhydrous inclusions, as well as their bond quality with the surrounding cement paste. The reduction of cement and silica fume was thus possible without impairing the micromechanical properties of the hydrates, by improving the particle packing density in the hardened state. As major conclusion, replacing cement and silica fume with GP and FGP without impairing both micro-scale and macro-scale mechanical properties provides a promising means to reduce the environmental footprint of current UHPC mix design.

Preliminary Characterization of Novel LDPE-Based Wear-Resistant Composite Suitable for FDM 3D Printing.

Low-density polyethylene (LDPE) composites reinforced with finely powdered waste glass were identified as a potential material for 3D printed structures for use in low-duty frictional applications. A recently published 3D printing model was used to calculate the limits in the filament feed rate and printing speed. Tribological tests (pin-on-disc method) of the printed composites were performed for different print-path directions. Differential scanning calorimetry (DSC) was performed on the samples and the composites showed a higher crystallinity compared with LDPE, which partially explains the higher elastic modulus of the composites determined during static tensile tests. Using a fine glass powder as reinforcement improved the wear resistance of LDPE by 50% due to the formation of a sliding film on the sample’s surface. An evident effect of friction direction vs. the printed path direction on wear was found; which was likely related to differences in the removal of friction products from the friction area for different print-path directions. The LDPE composites with fine waste glass particles are promising materials for low-duty frictional applications and should be the subject of further research.

Combined use of waste concrete and glass as a replacement for mortar raw materials

The construction industry offers one of the most attractive options in the use of recycled materials due to its large consumption of raw materials and high construction work rates. Also, the debris from construction and demolition is responsible for a high participation rate in the generation of waste, with concrete being a major contributor in this category. Waste glass powder, on the other hand, is a material that offers an excellent alternative to replace cement due to its well-known pozzolanic properties. Hence, the combined behaviour of fine recycled concrete aggregates and glass powder of different particle sizes in mortars has been studied. Different mixtures are analyzed with the aim of minimizing losses in mechanical properties and durability in an attempt to maximize the amount of replaced materials. Due to the delayed pozzolanic reaction by the glass powder, the samples present highly satisfactory results at 90 days of curing, with values of their properties close to those of the control mortar. The results are encouraging when glass powder with a smaller particle size is used due to its filler effect combined with its pozzolanic activity, making it possible to replace up to 20% of glass powder with a maximum size of 38 µm, with up to 30% of fine recycled concrete aggregates. Finally, the evaluation of greenhouse gases showed that the simultaneous incorporation of both types of waste reduces the CO2 emissions associated with concrete by up to 19%.

Glass powders and reactive silicone binder: Interactions and application to additive manufacturing of bioactive glass-ceramic scaffolds

A novel concept for the additive manufacturing of three-dimensional glass-ceramic scaffolds, to be used for tissue engineering applications, was based on fine glass powders mixed with a reactive binder, in the form of a commercial silicone. The powders consisted of ‘silica-defective glass’ specifically designed to react, upon firing in air, with the amorphous silica yielded by the binder. By silica incorporation, the glass was intended to reach the composition of an already known CaOsingle bondNa2Osingle bondB2O3single bondSiO2 system. Silica from the binder provided up to 15 wt% of the total silica. With the same overall formulation, silicone-glass powder mixtures led to nearly the same phase assemblage formed by the reference system, crystallizing into wollastonite (CaSiO3) and Ca-borate (CaB2O4). Samples from silicone-glass powder mixtures exhibited an excellent shape retention after firing, which was later exploited in highly porous reticulated scaffolds, obtained by means of direct ink writing (DIW).

ПЛАЗМОХИМИЧЕСКОЕ МОДИФИЦИРОВАНИЕ БЛОЧНЫХ ТЕПЛОИЗОЛЯЦИОННЫХ МАТЕРИАЛОВ С ДЕКОРАТИВНЫМ ПОКРЫТИЕМ

The impact of plasma of an arc plasmatron on plasmochemical modification of a two-layer heat-resistant decorative covering on the protecting foam glass blocks is investigated. The optimum technological parameters of plasma processing of such blocks with a preliminary basis of finely divided glass containers and high-quality glass breakage are determined. It is shown that the texture and quality of a two-layer heat-resistant decorative covering are affected by speed characteristics of the plasma torch. It is established experimentally that when the arc-plasma reflow rate is 5 mm /s, a continuous wavy coating is formed on the surface of the foam glass block, and at 10 mm /s – a continuous coating with even spill. Intermediate heat-resistant and basic compositions of decorative two-layer coating for plasma-chemical modification of enclosing blocks of heat-insulating materials have been developed. The intermediate heat-resistant structure includes the following ingredients: heat-resistant aluminous cement, crushed and fractioned high-aluminous refractory material, liquid glass. The basic structure includes mixture of fine ground glass powder of tare and high-quality glasses with the crushed high-aluminous refractory material. The following performance indicators are investigated: adhesion strength of the coating with the matrix, frost resistance, microhardness, acid resistance, water resistance, abrasion resistance, moisture resistance and resistance to neutral salt spray test.

Effective utilization of waste glass powder as the substitution of cement in making paste and mortar

The qualities reserved by the fine glass powder like amorphous structure, non-biodegradable nature, and easy availability in all places create new insight. It used as the pozzolanic material with the motive of resolving varied environmental issues, getting improved end product over traditional one. The key feature of the study is to examine the environmental impact when there is a decrease in particle size of 12 µ (75–63 µ) fine glass powder with substitution level 0–20% for O.P.C at paste and mortar regime. Research, findings suggested that the fresh properties are much influenced by fineness and morphology of glass powder. The hardened properties including pozzolanic reactivity are investigated by lime reactivity and compressive strength. Based on that GP63 is more reactive than GP75, besides this transverse strength, drying shrinkage and % water absorption of control and blended mortar was also carried out. The results of an environmental impact study of the control and blended paste signifying 20% reduction in indexes of the sustainable environment for glass powder mix at 20% as compared to control. SEM and EDX analysis behavior in early days (SEM micrograph) reveal identical morphology confirming its behavior as filler and with the growth of CSH compound later on signifying its pozzolanic nature. Comparison of result shows the mix having 63 µ glass powder is overall more efficient in replacing cement up to 20% with improved microstructure.

Extension of the 'Inorganic Gel Casting' Process to the Manufacturing of Boro-Alumino-Silicate Glass Foams.

A new technique for the production of glass foams, based on alkali activation and gel casting, previously applied to soda-lime glass, was successfully extended to boro-alumino-silicate glass, recovered from the recycling of pharmaceutical vials. A weak alkali activation (2.5 M NaOH or NaOH/KOH aqueous solutions) of fine glass powders (below 70 µm) allowed for the obtainment of well-dispersed concentrated aqueous suspensions, undergoing gelation by treatment at low temperature (75 °C). Unlike soda-lime glass, the progressive hardening could not be attributed to the formation of calcium-rich silicate hydrates. The gelation was provided considering the chemical formulation of pharmaceutical glass (CaO-free) to the formation of hydrated sodium alumino-silicate (N-A-S-H) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. A sintering treatment at 700 °C, was finally applied to stabilize the cellular structures.

Highly Porous Sr/Mg‐Doped Hardystonite Bioceramics from Preceramic Polymers and Reactive Fillers: Direct Foaming and Direct Ink Writing

Novel hardystonite‐based bioceramics are obtained by thermal treatment, in air, of silicone resins and reactive fillers. Using commercial silicones embedding SrO and MgO precursors, in addition to CaO and ZnO precursors, a quite complex solid solution (Ca1.4Sr0.6Zn0.85Mg0.15Si2O7) can be achieved, at 1100 °C, instead of pure hardystonite (Ca2ZnSi2O7), with improvements in biocompatibility and bioactivity. Highly porous foams are obtained by gas evolution at the early stage of heat treatment (at 300–350 °C), from the dehydration of active filler present in hydrated form (Mg(OH)2). Additionally, direct ink writing of silicone‐based pastes is used for the manufacturing of scaffolds with non‐stochastic pore architecture. In the latter case, strong scaffolds (with compressive strength exceeding ≈12 MPa) are obtained by adding fine glass powders as an additional filler. This addition enhances the viscous flow upon firing, but do not compromise the phase evolution, owing to the exact match in the composition between glass and silicone/filler mixture.

Bioactive glass-ceramic scaffolds by additive manufacturing and sinter-crystallization of fine glass powders

Abstract

Porous glass-ceramics from alkali activation and sinter-crystallization of mixtures of waste glass and residues from plasma processing of municipal solid waste

Abstract Alkali-activated aqueous slurries of fine glass powders, mostly deriving from the plasma processing of municipal solid waste (‘Plasmastone’), were found to undergo progressive hardening at low temperature (75 °C) owing to the formation of C S H (calcium silicate hydrate) gels. Before complete setting, slurries could be easily foamed by vigorous mechanical stirring, with the help of a surfactant; finally, the resulting open-celled structure could be ‘frozen’ by a subsequent sintering treatment, with crystallization of Ca Fe silicates. The densification of the struts upon firing was enhanced by mixing Plasmastone with up to 30 wt% recycled glasses and increasing the firing temperature from 800 to 1000 °C. A total porosity exceeding 75 vol%, comprising both well-interconnected macro- and micro-sized pores on cell walls, was accompanied by good compressive strength, well above 1 MPa. The stabilization of pollutants generally increased with increasing firing temperature and glass content, with some exceptions; no practical leaching was observed from samples deriving from Plasmastone combined with 30 wt% boro-alumino-silicate glass from the recycling of pharmaceutical vials.

Is open-loop recycling the lowest preference in a circular economy? Answering through LCA of glass powder in concrete

Abstract The government of Quebec (Canada) is trying to find a useful outlet for the mixed waste glass pilling up in its landfills. One solution to consider is the use of fine glass powder from mixed waste glass as alternative cementitious materials (ACM) in concrete, using an open-loop circular-economy principle. To quantify the environmental feasibility of this concept, life cycle assessment (LCA) methodology, in combination with a real case study (i.e., a concrete sidewalk in Montreal, Canada) are both assessed. More specifically, two different scenarios are compared, the business-as-usual (BAU) concrete production model, and a glass powder (GP) concrete production process model. All modeling efforts are performed using SimaPro 8.2 software, the Ecoinvent 3.2 database and the IMPACT 2002 + impact method. Finally, a Monte Carlo simulation, in addition to different sensitivity analyses, are carried out to assess the influence of data uncertainty and key parameter changes, such as the distance from suppliers, potential lifetime extension of the concrete, and possible particulate emissions during GP production. Results show the environmental benefits of using GP as an ACM in terms of every indicator. Moreover, the significant contribution of cement production in the environmental burden of concrete is noted. It appears as the main hotspot in most midpoint indicators, and in all four endpoint indicators. It is especially highlighted as a global warming indicator, with 74% of the greenhouse gasses (GHG) related to cement production for the BAU scenario and 68% for the GP scenario. The emissions of particles into the atmosphere (such as CO2, NOx, and SOx) from the clinker kiln chimney plays a major role in the overall environmental impact of concrete production. Another key result is the importance of transportation distance of the base materials, which could reverse the conclusion. The originality of this paper relies on the environmental assessment of the up-cycling of GP as a supplementary cementitious materials (SCM) in concrete. Indeed, this study allows for a better understanding of environmental impact of concrete and highlights the extent to which environmental benefits remain when mixed waste glass is used in an open-loop circular-economy context. At a larger scale, this study aims to encourage all municipalities/government that are struggling with common waste – such as mixed waste glass -- to find industrial symbioses at a local scale.

Selective laser melting of fiber-reinforced glass composites

A selective laser melting (SLM) process is developed for manufacturing of a novel glass fiber-reinforced glass (GRFG) composite material. Experiments using a continuous wave fiber laser are conducted for demonstrating this SLM process using borosilicate S-glass fibers and fine soda lime glass powders, which have distinct glass transition temperatures. During laser scanning, fine glass powders turn into viscous flow. The molten glass flows through and encapsulates the relatively solid fibers, which are not fused due to their relatively higher glass transition temperature. Upon cooling, a compacted GRFG composite forms with a high volume ratio of intact and well-encapsulated glass fibers.

Using glass powder to improve the durability of architectural mortar prepared with glass aggregates

This study designed a novel cement-based architectural tile prepared with more than 70% waste glass content (by weight). The waste glass was employed not only as decorative aggregates but also as a supplementary cementitious material in the architectural mortar. In terms of shrinkage, the incorporation of glass powder (GP) could significantly reduce the drying shrinkage of the glass mortars regardless of its fineness. When the glass mortars were subjected to high temperature (800°C), the inclusion of GP into the mortars was more able to mitigate the flexural and compressive strengths losses as compared to the control glass mortar prepared without the use of GP. Furthermore, using the GP and glass aggregates simultaneously could effectively improve the resistance of the glass mortars to sulfuric acid attack and the positive effect was more pronounced when finer GP was incorporated. In particular, an encouraging result shows that the replacement of 20% cement by fine GP successfully suppressed the deteriorative alkali-silica-reaction (ASR) expansion caused by the glass aggregates. Also, the glass mortars incorporated with fine GP exhibited comparable or even superior durability properties than that of the fly ash blended glass mortar.

Partial substitution of silica fume with fine glass powder in UHPC: Filling the micro gap

The design of ultra-high-performance concrete (UHPC) depends basically on the packing density and particle-size distribution (PSD) of its ingredients. The PSD of cement exhibits a gap at the micro scale that needs to be filled with finer materials such as silica fume (SF). Filling this gap solely with SF requires a high amount of SF (25% to 30% by wt. of cement) due to its extreme fineness. The use of high SF volume negatively effects concrete rheology. In addition, the limited resources and high cost of SF impede the wide use of UHPC in concrete market. This paper reports on a study to determine the possibility of producing and using fine glass powder (FGP) as a SF partial replacement in UHPC. The results show that FGP with a mean particle size (d50) of 3.8µm could be recommended as an optimal PSD to fill the gap between cement and SF particles. The results demonstrate that compressive strength values of 235 and 220MPa under 2days of steam curing can be achieved, respectively, when replacing 30% and 50% of SF with FGP, compared to 204MPa for the reference UHPC containing 100% SF. The rheology of fresh UHPC is improved by replacing SF particles with nonabsorptive glass particles.

Properties of high volume glass powder concrete

Mechanical and durability properties of concrete with cement replaced by finely grounded glass powder in high volume up to 60% were investigated. XRD and TGA analyses indicated that the fine glass powder reacted with calcium hydroxide to form calcium-silicate-hydrates. As such, the microstructures of concrete were more compact and homogeneous, especially at the interfacial transition zone. Concrete with cement replaced by 15% and 30% glass powder exhibited the highest strength increase and correspondingly the lowest porosity. Beyond a replacement of 30%, calcium hydroxide became insufficient for the pozzolanic reaction of glass powder. However, the high volume glass powder concrete retained distinct resistance against water and chloride ingress, due to the reduction in pore size and connectively. Reductions of 77%, 83%, 96%, 91% and 92% were observed respectively for water penetration depth, sorptivity, conductivity, chloride diffusion and migration coefficients in concrete with cement replaced by glass powder by 60%.

SEM Analysis of the Interfacial Transition Zone between Cement-Glass Powder Paste and Aggregate of Mortar under Microwave Curing

In order to investigate the effects of microwave curing on the microstructure of the interfacial transition zone of mortar prepared with a composite binder containing glass powder and to explain the mechanism of microwave curing on the improvement of compressive strength, in this study, the compressive strength of mortar under microwave curing was compared against mortar cured using (a) normal curing at 20 ± 1 °C with relative humidity (RH) > 90%; (b) steam curing at 40 °C for 10 h; and (c) steam curing at 80 °C for 4 h. The microstructure of the interfacial transition zone of mortar under the four curing regimes was analyzed by Scanning electron microscopy (SEM). The results showed that the improvement of the compressive strength of mortar under microwave curing can be attributed to the amelioration of the microstructure of the interfacial transition zone. The hydration degree of cement is accelerated by the thermal effect of microwave curing and Na+ partially dissolved from the fine glass powder to form more reticular calcium silicate hydrate, which connects the aggregate, calcium hydroxide, and non-hydrated cement and glass powder into a denser integral structure. In addition, a more stable triangular structure of calcium hydroxide contributes to the improvement of compressive strength.

Fabrication of highly insulating foam glass made from CRT panel glass

We prepared low-density foam glasses from cathode-ray-tube panel glass using carbon and MnO2 as the foaming agents. We investigated the influence of the carbon and MnO2 concentrations, the glass-powder preparation and the foaming conditions on the density and homogeneity of the pore structure and the dependence of the thermal conductivity on the foam density. The results show that the moderate foaming effect of the carbon is greatly improved by the addition of MnO2. A density as low as 131kgm−3 can be achieved with fine glass powder. The foam density has a slight dependence on the carbon and MnO2 concentrations, but it is mainly affected by the foaming temperature and the time. The thermal conductivity of the foam-glass samples is lower than that of commercial foam glasses with the same density. The lowest value was determined to be 42mWm−1K−1 for a foam glass with a density of 131kgm−3. A further improvement in the closed porosity could potentially decrease the thermal conductivity even further, and thus our approach has great potential in terms of a thermal insulation material.