The drainage consolidation method has been efficiently used to deal with soft ground improvement. Nowadays, it has been suggested to use a new sand soil which is a composite of sand and recycled glass waste. The permeability performance of glass-sand soil was explored to judge the feasibility of glass-sand soil backfilled in the drainage consolidation of sand-drained ground. For comparison purposes, different mix proportions of recycled glass waste, fineness modulus, and glass particle size were analyzed to certify the impact on the permeability coefficient and the degree of consolidation. The numerical results show that adding a proper amount of recycled glass waste could promote the permeability performance of glass-sand soil, and the glasssand soil drain could be consolidated more quickly than a sand drain. Experiments showed that glass-sand soil with the a 20% mix of recycled glass waste reveals the optimum performance of permeability.
The implementation of a new, high-performance float flat glass manufacturing technology in Europe, in conjunction with the growing interest in new glass functions expressed by the construction industry, has led to significant developments in the theory of glass structures. Long time research conducted in the EU countries has been concluded by the technical document CEN/TC 250 N 1060, drawn up as a part of the work of the European Committee for Standardization on the second edition of Eurocodes (EC). The recommendations pertaining to the design of glass structures have been foreseen in the second edition of the Eurocodes, in particular the development of a separate design standard containing modern procedures for static calculations and stability of glass building structures (cf. works M. Feldmann, R. Kasper, K. Langosch and other).
In this paper new static analysis methods for glass plates made of monolithic and laminated glass, declared in th document CEN/TC 250 N 1060 (2014) and recommended in the national standarization document CNR-DT 210 (National Research Council of Italy, 2013) are presented. These static analysis methods are not commonly known in our national engineering environment, and thus require popularization and regional verification. Numerical and analytical simulations presented in this paper for rectangular plates made of monolithic and laminated glass and having various support conditions are of this character. The results of numerical calculations constitute a basis for the discussion of new static analysis methods for plates.
The paper focuses on the development of knowledge about the hot bending of curved architectural glass produced by the slumping process and the challenges as well as the limitations thereof. Due to the complexity of the process, many factors influence the final quality of the glass and the main objective was to better understand the procedure itself in order to improve the control and quality of the slumping process. As a result of the growing interest in this type of glass for architectural applications, the glass processing market is increasingly investing in the required technology. For the moment, this growing niche does not have a large number of direct explanations of the glass behaviour in the furnace in the available literature, which in turn encourages cooperation between the scientific community and manufacturers. This paper presents the conducted experiments that have led to a better understanding of the furnace's work and the impact of specific factors on its operation. Based on the 3D numerical model, a large sample of glass was produced, which was then scanned with a 3D laser using a method developed for the experiment. The results suggested that a more accurate test with usage of a full-size furnace is required. Based on this, the experiment was carried out using a large number of glass samples of different thicknesses. The results of the experiment helped to better understand and demonstrate the need for further research of this technology in order to optimize the quality of the process.
The nanocomposites based on water glass matrix were attempted in the study. Nanoparticles of ZnO, Al2O3 or MgO in organic solutions
were applied into water glass matrix in the amounts of: 1.5; 3; 4 or 5 mas. %. Wettability of the quartz sad by the nanocomposites based on
water glass matrix was determined by testing changes of the wetting angle θ in time τ for the system: quartz – binder in non-stationary
state, by means of the device for measuring wetting angles. Wettability measurements were carried out under isothermal conditions at an
ambient temperature (20 – 25 oC). The modification improves wettability of quartz matrix by water glass, which is effective in improving
strength properties of hardened moulding sands. Out of the considered modifiers in colloidal solution of propyl alcohol water glass
modified by MgO nanoparticles indicated the smallest values of the equilibrium wetting angle θr. This value was equal app. 11 degrees and
was smaller no less than 40 degrees than θr value determined for not modified water glass. Viscosity η of nanocomposites based on water
glass matrix was determined from the flow curve, it means from the empirically determined dependence of the shearing stress τ on shear
rate γ: τ = f (γ) (1), by means of the rotational rheometer. Measurements were carried out at a constant temperature of 20 oC. The
modification influences the binder viscosity. This influence is conditioned by: amount of the introduced modifier as well as dimensions and
kinds of nanoparticles and organic solvents. The viscosity increase of the modified binder does not negatively influence its functional
properties.
Presented are results of a research on usability of an innovative reclamation process of microwave-hardened moulding sands containing
water-glass, combined with activation of binder. After each subsequent stage of reclamation, quality of the reclaimed material was
determined on the grounds of measurements of permeability and results of screen analysis. The reclaimed material was next used again to
prepare new moulding sand. The sandmix based on high-silica sand prepared with water-glass grade 145, was subject to the following
cyclical treatment operations: mixing components, consolidation, microwave hardening, cooling, heating the mould up to 800 °C, cooling
to ambient temperature, mechanical reclamation dry and wet. It was found that the used-up and reclaimed sandmix containing water-glass
is susceptible to the applied activation process of thermally reacted film of binder and, in addition, it maintains good quality and
technological properties of high-silica base. Observations of surfaces of reclaimed high-silica grains with activated film of reacted
inorganic binder were carried-out using a scanning microscope. Thanks to properly selected reclamation parameters, the high-silica base
can be reused even five times, thus reducing demand for fresh aggregate and inorganic binder.
In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands
containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45
GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium
water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of
wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like
permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces
of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by
microwave heating
The durability characteristics of Engineered Cementitious Composites (ECC) with various fibers such as polypropylene and glass were investigated in view of developing composites with high resistance to cracking. ECC offer large potential for durable civil infrastructure due to their high tensile strain capacity and controlled micro-crack width. In this study, fibre volume fractions (0.5%, 1%, 1.5%, and 2%) of both polypropylene and glass fibers varied and durability measures such as a rapid chloride penetration test, sorptivity, water absorption, acid attack, and sulphate attack were measured. Increasing the fiber content up to 1.5% improved the durability properties of ECC. The test results indicate that the glass fiber-reinforced Engineered Cementitious Composites have better durability characteristics than polypropylene fiber-reinforced ECC.
The paper presents research of metallic glass based on a Mg72Zn24Ca4 alloy. Metallic glass was prepared using induction melting and further injection on a spinning copper wheel. The X-ray diffractometer and differential scanning calorimeter (DSC) were used to investigate the phase transformation of the amorphous ribbon. The heat released in the crystallization process, during isothermal annealing, based on the differential scanning calorimeter investigation, was determined to be 166.18 Jg-1. The effect of isothermal annealing temperature on the kinetics of the amorphous alloy crystallization process using differential scanning calorimeter was investigated. For this purpose, two isothermal annealing temperatures were selected. The incubation time decreases as the temperature of the isothermal annealing increases from 300 to 252 seconds. The same relationship is visible in the case of duration of the phase transformation, which also decreases as the temperature of the isothermal annealing increases from 360 to 228 seconds. The obtained results show a significant influence of isothermal annealing temperature on the degree of phase transformation.
In the paper, an attempt is made to explain the previously observed increased effectiveness of utilising hydrated sodium water-glass grade
137 after hardening moulding sands with selected physical methods. In the modified process of preparing sandmixes, during stirring
components, water as a wetting additive was introduced to the sand-binder system. Presented are examination results of influence of faster
microwave heating and slower traditional drying of the so-prepared moulding sands on their tensile and bending strength, calculated per
weight fraction of the binder. The measurement results were confronted with SEM observations of linking bridges and with chemical
analyses of grain surfaces of high-silica base. On the grounds of comprehensive evaluation of hardened moulding sands, positive effects
were found of the applied physical process of binder dehydration and presence of the wetting additive. It was observed that introduction of
this additive during stirring, before adding the binder, improves flowing the binder to the places where durable linking bridges are created.
It was also found that the applied methods of hardening by dehydration enable creation of very durable linking bridges, strongly connected
with the sand base, which results in damages of high-silica grain surfaces, when the bridges are destroyed.
The aim of the study was to determine the applicability of a new product added to water glass-containing foundry sands hardened with
ethylene glycol diacetate. The new additive designated by the symbol "B" is a composition of aqueous solutions of modified polyalcohols,
improving the sand knocking out properties. The scope of studies included testing various mechanical and technological properties
of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties.
In the technological studies, two types of water glass with different values of the silica modulus and density, designated as R145 and R150,
were used. Moulding sands were prepared with the additive "B". For comparison, reference sands with water glass but without the additive
"B" were also made. In Part I of the article, the results of studies of the effect of additive "B" on the properties of foundry sands with water
glass hardened by CO2 blowing were discussed.
The article takes into consideration the researches concerning inserting the Glassex additive to the microwaved-hardened and selfhardened moulding sands with water glass. In the research different types of ester hardeners to self-hardened moulding sands with water glass were used. The influence of Glassex additive on retained strength of moulding sands with different hardeners and prepared by different technologies of hardening were tested. The influence of different hardeners and the technology of hardening on retained strength of moulding sand with water glass and the Glassex additive were also estimated.
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