Waste Soda Lime Research Articles

Life cycle assessment of silica aerogel produced from waste glass via ambient pressure drying method

Silica aerogels are excellent insulation materials, but they possess high embedded costs and their production includes many energy-intensive steps. A novel protocol developed to produce silica aerogel from waste soda lime glass via ambient pressure drying was assessed regarding sustainability. Upcycling waste materials and implementing a low-energy drying technique are aimed at increasing the sustainability of aerogels. This study presents a cradle-to-gate life cycle assessment (LCA) of this process on a laboratory scale (reactor volume of 0.5 l) as well as on a modeled industrial scale (reactor volumes of 100 l and 1000 l). The environmental impacts associated with each scale, as well as with each step of the production, were calculated and summarized with an environmental cost indicator in euros for each process. Potential end-of-life scenarios were considered to explore waste treatment approaches. Results show that electricity consumption is a major contributor to environmental impact, especially at the laboratory scale. However, at the industrial scale, efficiency is significantly improved, thereby drastically decreasing the impact of electricity. Additionally, the contributions of raw materials have a larger environmental impact than those of waste disposal, indicating that it is crucial to focus on the reduction and re-usage of reactants and solvents.

Study on fresh and hardened state properties of eco-friendly foamed concrete incorporating waste soda-lime glass

Improper waste management is causing global environmental problems. Waste glass may have adverse impacts on the ecosystem. While a substantial amount of soda-lime glass bottle (SGB) undergoes recycling to create new glass items, a significant volume still ends up in landfills. Therefore, the aim of this study was to explore the potential use of SGB in foamed concrete (FC) production as an aggregate replacement. SGB was substituted for sand in different weight fractions, ranging from 5 to 50%. The fresh state, mechanical, thermal, pore structure, and transport properties were examined. The findings showed a significant enhancement in the FC’s mechanical properties when SGB replaced 20% of sand. The compressive, flexural, and splitting tensile strengths exhibited a rise of up to 17.7, 39.4, and 43.8%, respectively. The findings also demonstrated that the addition of SGB improved the thermal conductivity, sorptivity, water absorption, and porosity. The scanning electron microscopy analysis indicated that the inclusion of 20% SGB caused a substantial decrease in void diameter and enhanced its uniformity. A comparison was made between the experimental data and predictions of the mechanical properties using various models of international standards, such as IS 456, ACI 318, NZS-3101, EC-02, AS 3600, and CEB-FIB, along with several references in the literature. The findings implied a strong correlation between the strength properties. The outcomes of this research offer valuable insights into both the possible advantages and constraints of using SGB in FC. Furthermore, this extensive laboratory investigation may serve as a guideline for future study and aid in the advancement of greener and more environmentally friendly FC alternatives.

Immobilization of simulated 137Cs in waste soda-lime glass modified by Ca, Ba, and B2O3

Immobilization of simulated 137Cs in waste soda-lime glass modified by Ca, Ba, and B2O3

Strength improvement of clay using waste soda lime glass powder and sodium alginate

Clayey soil is generally weak in nature. When constructions are carried out on clayey soil, especially highways, railways, buildings and embankment face many difficulties. Therefore, the improvement of such type of soil is crucial. Soil stabilization can be done by different methods, which includes stabilization using lime, cement and waste materials from various industries etc. Soda lime glass powder is a waste material from glass industries. Clay is a type of soil that can be categorized as problematic due to its weak properties like volumetric expansion, low strength etc. In this soil, the shear strength of the soil is less due to its very high initial moisture content and plasticity. Construction is difficult in such type of weak clay. The main aim is to identify the properties of clay. And, to study the effect of waste soda lime glass powder (WSLGP) and sodium alginate (SA) on clay. Standard proctor compaction test and Unconfined strength test is carried out using varying (3%, 6%, 9%, 12%, 15%) percentages of WSLGP and optimum WSLGP content is determined. The sodium alginate in varying (0.25%, 0.5%, 0.75%, 1%, 1.25%) percentages is added to clay with optimum soda lime glass powder. Standard proctor compaction test and Unconfined compressive strength test were carried out. The maximum strength is obtained at optimum 12% WSLGP and 1% SA content.

Recycling of arsenic residue and waste soda-lime silicate glass via vitrification

Vitrification is an environmental friend way to solidify arsenic residue (AR). In this work, instead of solidification/stabilization (S/S), we further explored the feasibility of recycling AR and waste soda-lime silicate (SLS) glass via vitrification. First, the purified AR (5–25 wt%) and waste SLS glass were melted in a closed electric furnace and successfully quenched to glass sheets. To verify the thermal, mechanical, and chemical stability of the prepared As-containing SLS glass samples, differential scanning calorimetry (DSC), nanoindentation, and water leaching experiments were performed, respectively. Results show that, with the increase of As concentration, the phase-separation phenomenon was enhanced and glass structure stability was decreased due to the formation of [AsO4] tetrahedral units (replacing [SiO4]). Nevertheless, all the recycled As-containing SLS glass samples remain amorphous and own comparatively high visual transparency (>86%), nano-hardness (> 7 GPa) and elastic modulus (> 80 GPa). Moreover, based on the dynamic and static water leaching experiments, the recycled glass sample containing 5 wt% of purified AR shows the lowest amount of leaching As (1.38 mg/L at 22±3 °C for 313 days) which has the potential for future application including building windows.

Preparation of an environment-friendly LTCC material by using waste soda-lime glass and natural volcanic ash

Glass/ceramic composites applied in the field of low-temperature co-fired ceramics (LTCC) were successfully prepared at 670–710 °C by using waste soda-lime glass (WG) as a binder and natural volcanic ash as a ceramic raw material. Based on the theories of suppression and supplementary network effects, alkaline-earth metal ions (R2+, R = Mg, Ca, Sr, and Ba) and B2O3 were applied to improve the dielectric properties of WG and composites, respectively. The influence of R2+ on the crystal phase evolution, microstructure, mechanical, dielectric, and thermal properties of WG-volcanic ash-based composites were systematically investigated. By doping 2.5 wt% Ba2+ to the environment-friendly LTCC composites, physical properties i.e., εr of 4.86 at 1 MHz, tan δ of 6.32 × 10−3, coefficient of thermal expansion of 8.72 × 10−6/°C, and thermal conductivity of 1.04 W/(m·K) are obtained. It is worth mentioning that the environment-friendly LTCC composite uses WG with a low glass transition temperature to reduce the sintering temperature and a tiny amount of a modifier to adjust the dielectric performance instead of synthesizing specific crystals by adding lots of chemical reagents. These, in turn, do not only have the potential to be used in the LTCC packaging technology but also have significance for sustainable development. Additionally, because of good chemical compatibility between aluminum and the composites, the environment-friendly LTCC composites with ultra-low sintering temperature have the potential ability to lower the cost of LTCC packaging materials.

Effects of Waste Glass Powder as Pozzolanic Cement Supplementary Material for Structural Elements

The ever-growing global production of glass generates high waste percentages, the vast majority of which does not get recycled hence increasing the concern on its environmental impact. Studies on the pozzolanic properties of glass powder emerged as a solution to the abundance of waste glass powder available and its insufficient recycling. The aim of this study is to investigate the influence 10% ,15% and 20% of waste soda-lime glass powder as partial cement replacement; fresh concrete tests were carried out, as well as compression strength tests at 28 days on grade 280 kg/cm2 concrete produced with pozzolanic cement. Tests results show an insignificant reduction of slump on the concrete mixes, an increase of air content and a decrease in density and compressive strength resistance with increasing glass powder substitution.

Development of Novel Transparent Radiation Shielding Glasses by BaO Doping in Waste Soda Lime Silica (SLS) Glass

In the current study, BaO was doped in Bi2O3-ZnO-B2O3-SLS glass to develop lead-free radiation shielding glasses and to solve the dark brown of bismuth glass. The melt-quenching method was utilized to fabricate (x) BaO (1 − x)[0.3 ZnO 0.2 Bi2O3 0.2 B2O3 0.3 SLS] (where x are 0.01, 0.02, 0.03, 0.04, and 0.05 mol) at 1200 °C. Soda lime silica glass waste (SLS), which is mostly composed of 74.1% SiO2, was used to obtain SiO2. The mass attenuation coefficient (μm) was investigated utilizing X-ray fluorescence (XRF) at 16.61, 17.74, 21.17, and 25.27 keV and narrow beam geometry at 59.54, 662, and 1333 keV. Moreover, the other parameters related to gamma ray shielding properties such as half-value layer (HVL), mean free path (MFP), and effective atomic number (Zeff) were computed depending on μm values. The results indicated that HVL and MFP decreased, whereas μm increased with an increase in BaO concentration. According to these results, it can be concluded that BaO doped in Bi2O3-ZnO-B2O3-SLS glass is a nontoxic, transparent to visible light, and a good shielding material against radiation.

Foam glass derived from ferrochrome slag and waste container glass: Synthesis and extensive characterizations

Lately, energy-saving attempts in the construction and building materials industry have become more popular due to the diminishing natural resources. With this motivation, we investigated the first foam glass consisting of ferrochrome slag (FS) and waste soda-lime glass (SLG) for potential use as a heat insulation material. For this, FS and SLG waste materials were valorized as main constituents, whereas a mixture of water glass (WG) & glycerol (G) and a sufficient amount of water (W) was used as a foaming agent and a moisturizer in the batch mixture, respectively. The studied series was prepared with the composition of 20FS-70SLG-xG-(8-x)WG-2W where x: 2, 4, and 6 wt%. After that, three different process temperatures (800, 825, and 850 °C), two distinct heating rates (5 and 10 °C/min), and two discrete dwell times (15 and 30 min) paved the way for the synthesis of 36 different foam glass samples. Eventually, the fabricated 36 different samples were subjected to physical, thermal, mechanical, and microstructural evaluations. According to the findings, one can say that samples synthesized with a lower G-to-WG ratio, higher process temperature, lower heating rate, and higher dwell time have the best features. From the physical property determinations, we found out that bulk density (ρbulk) varied between 233 and 903 kg m−3 while the estimated porosity (P) ranged from 59.4 to 89.5%. Further, thermal conductivity (k) measurements demonstrated that the fabricated foam glass series provides lower values, namely from 0.038 to 0.130 W m−1 K−1. Besides, compressive strength (CS) values were found to be changing from 0.127 to 2.225 MPa. Microstructural evaluations via scanning electron microscopy (SEM) revealed the pore formations and the relevant alterations as a result of the different parameters. All in all, the authors concluded that a heat insulation material composed of nearly fully waste substances can effectively be produced.

Effects of Waste Soda-Lime Glass Sand and Glass Fiber on Physical and Mechanical Properties of None-Autoclaved Aerated Concrete

This paper investigates the combined effect of waste soda-lime glass sand and glass fiber on the physical and mechanical properties of none-autoclaved aerated concrete (NAAC). The use of both soda-lime glass sand and glass fiber can provide silica-rich materials in the aerated concrete and can enable the elimination of an autoclaved curing by enhancing the physical and mechanical properties in aerated concrete. In this study, a total of six mixture proportions were designed to evaluate these properties in NAAC. The mixture parameters included the partial substitutions of normal sand with soda-lime glass sand (0%, 15%, and 30%) and glass fiber (1%, 2%, and 3%). A series of tests were conducted to determine density, absorption, porosity, and both compressive and flexural strengths of the NAAC. Test results present that the increase of glass sand content leads to the increasing of both compressive and flexural strengths. Moreover, the combination of the use of glass sand with glass fiber also increases the strength up to 2 times (the mixture of 30% glass sand and 3% glass fiber). Furthermore, test results indicate the relatively good relationship between the density, porosity, and of NAAC with good accuracy.

Monte Carlo simulation of radiation shielding properties of the glass system containing Bi2O3

Monte Carlo simulation is an important tool to obtain some parameters of a material, especially when it is impossible to perform an experiment. Radiation shielding of a material has been very important properties as the radiation started to be used in a variety of different fields. Besides using it in different fields, thus protection from its hazardous effects becomes a popular subject for researchers. For this purpose, there have been many different works done for different types of materials. Glass is an important material, and it is interesting to investigate its radiation shielding properties. Thus, in the present study, waste soda–lime–silica-based glasses (SiO2–Na2O–CaO–Bi2O3) were calculated using MCNP simulation code, and the results were compared with the XCOM calculation results.

Radiation shielding competencies for waste soda–lime–silicate glass reinforced with Ta2O5: experimental, computational, and simulation studies

In this study, the authors emphasized an incisive purpose as the valorization of waste soda–lime–silicate glass (SLS) for a potential gamma-rays shielding material. For this, xTa2O5-(100-x)SLS glass systems where x: 0, 0.005, 0.05, and 0.5 wt% were fabricated via conventional melting technique. The synthesized four glass specimens (RG and RGT1 to RGT3) were then subjected to physical, optical, and radiation shielding measurements. Simulation studies (MCNP-5) and theoretical computations (XCOM) were conducted to validate the findings. The results clearly showed that the insertion of Ta2O5 improved both physical and optical properties. In particular, RGT3, having a higher amount, possessed the highest glass density (ρglass) and refractive index (n) values. On the other hand, the transmission factor (TF) data revealed that increasing the thickness of the glass sample caused a notable decrease in the TF values. RG decreases from 92.233% to 78.461%, 61.562%, and 48.302% for thicknesses of 0.5 cm, 1.5 cm, 3 cm, and 4.5 cm. RGT3 shows the best radiation shielding potential out of the investigated waste SLS samples according to the several radiation shielding factors.

Evaluation of gamma-rays attenuation competences for waste soda-lime glass containing MoO3: Experimental study, XCOM computations, and MCNP-5 results.

The present work aims to examine a waste soda-lime-silica (SLS) glass system containing varying amounts of MoO3 for its potential use in radiation shielding applications. A series of 4 different glasses (RG, RGM1 to RGM3) were prepared. The starting materials were precisely weighed and mixed homogeneously. The glass samples were then synthesized by melting the mixtures in a Au-Pt crucible via a conventional electrical resistance furnace at 1300 C. The fabricated glasses were analyzed by performing physical and chemical measurements. Some glass property calculations were done to reveal the effect of changing the contents of MoO3. According to the results, all the fabricated SLS glass samples showed an amorphous structure with a suitable transparent appearance. The density and refractive index values increased as the amount of MoO3 in the glass systems increased. Moreover, the gamma-ray shielding ability of the SLS glass network was evaluated experimentally using a NaI (Tl) detector. The measured values of the linear attenuation coefficient (LAC) were confirmed using MCNP-5 simulation code and XCOM program. The LAC increased from 0.184 to 0.235 cm−1 when increasing the MoO3 ratio from 0 to 0.5 wt%, respectively. An agreement between the experimental measurements and theoretical calculations was achieved. The difference between the experimental and theoretical values was within 5 %. Based on the experimental LAC and other essential parameters, such as the half-value layer (∆0.5), mean free path (MFP), transmission factor (TF), and radiation protection efficiency (RPE), the radiation shielding ability of the investigated SLS glass system was determined.

The effect of Nb2O5 on waste soda‐lime glass in gamma‐rays shielding applications

Transparent waste soda-lime glass (SLS) reinforced with Nb2O5 (0.005, 0.05, and 0.5 wt%) was successfully synthesized using a conventional melting technique for gamma-radiation attenuation applications. The synthesized glass series (RG, RGN1 to RGN3) were then subjected to some physical, optical, and radiation shielding measurements. The physical measurements and computations showed that the increasing content of Nb2O5 increased glass density (ρglass), molar volume (Vm), and oxygen molar volume (OMV), however, decreased oxygen-packing density (OPD). Moreover, several optical parameters, such as the refractive index (n), dielectric constant (ϵ), and metallization criterion (M), were evaluated. One can say that the optical and physical properties can be improved owing to the addition of Nb2O5 in waste SLS glass. The gamma-ray transmission method was utilized to measure the linear attenuation coefficient (LAC) for the fabricated RGN glass series for gamma-photon energies 0.662, 1.173, and 1.332 MeV emitted from 137Cs and 60Co, respectively. The accuracy of the obtained results was tested by comparing the experimental data with those simulated by MCNP-5 and those computed theoretically by XCOM. The obtained results showed agreement between the experimental measurements, simulated, and theoretical evaluations. We found that the photons with energy of 0.662 MeV have a lower penetration power. Thus, the LACs are higher at 0.662 MeV for all synthesized glass samples. The LAC values at 0.662 MeV were between 0.1849 and 0.2253 cm− 1 for the glass samples RG and RGN3. The LAC results depicted a significant relationship between the chemical composition and the synthesized glass series’ attenuation coefficients. The LAC’s measured values were enhanced with the insertion of the niobium pentoxide (Nb2O5) contents. The half-value layer (HVL, ∆0.5) was calculated for the synthesized glass series based on the measured LAC. The thinner ∆0.5 layers were achieved at 0.662 MeV and ranged between 3.077 and 3.748 cm for the glasses coded as RGN3 and RG, respectively, while the thicker ∆0.5 layers were found at 1.332 MeV and changed in the range of 4.306–4.914 cm. The influence of the Nb2O5 doping ratio was examined, and we found that the values of the ∆0.5 layers become thinner as the Nb2O5 doping ratio increases.

Monte Carlo simulation of a waste soda–lime–silica glass system containing Sb2O3 for gamma-ray shielding

Gamma radiation has destructive effects on persons who are exposed to it and can cause damage to healthy tissues. Therefore, shielding materials are necessary for protecting against it. For this purpose, the attenuation characteristics of S-type glass – namely, soda–lime–silica glass (SLS) – which was doped with antimony (III) oxide (Sb2O3) were obtained by using the MCNPX code, and the results were compared with the XCOM software findings. The results of the attenuation parameters for four types of glass materials – namely, SLS (no addition of antimony (III) oxide), SLSS1 (0.005% antimony (III) oxide), SLSS2 (0.05% antimony (III) oxide) and SLSS3 (0.5% antimony (III) oxide) – show that with increasing energy levels, the linear attenuation coefficient decreases. For lower energy, μ has a sharp decrease, but the curve behavior is stable at higher energy. The XCOM calculations were done for a wide range of energies between 1 and 1 × 108 keV. Moreover, it is observed that the variations in the composition rates that lead to changes in the density of the glass system can affect the linear attenuation coefficients. Based on the obtained results of the linear attenuation coefficients, other parameters of the glass system such as the half-value layer and the tenth-value layer for the energies of 662, 1173 and 1332 keV were calculated. Additionally, the results also show that with increasing antimony (III) oxide contents, the thickness of the glass decreases.

Theoretical and experimental gamma-rays attenuation characteristics of waste soda-lime glass doped with La2O3 and Gd2O3

The present study explored the gamma-rays shielding characteristics of waste soda-lime glass (SLG) containing lanthanum oxide (La2O3) and gadolinium oxide (Gd2O3) by utilizing theoretical and experimental determinations. For this purpose, both La2O3, and Gd2O3 were separately added as 0.005, 0.05, and 0.5 wt% in place of waste SLG. The glass series of SLGL and SLGG were successfully fabricated via conventional melting techniques. Some physical analyses were done while radiation shielding parameters were figured out by using gamma-rays spectroscopy and XCOM computations to the produced glass specimens. One can easily state that the synthesized glasses showed a transparent appearance without any glass defects. Further, the glass density revealed an increasing trend with the insertion of both substances, but the SLGG series enhanced more. According to the experimental measurements, it was figured out that both oxide additions had the ability to increase the linear attenuation coefficient (LAC) values. The LAC was improved from 0.151 to 0.242 cm−1 for Gd2O3 insertion ration whereas 0.148 to 0.202 cm-1 for La2O3 series. Moreover, a good agreement between the experimental measurements and theoretical calculations was fulfilled. Based on the measured LAC values, other important parameters including mass attenuation coefficient (MAC), half-value layer (HVL), and mean free path (MFP) were evaluated for the investigated glass series. All in all, the authors concluded that SLGG3 glass can compete with commercial radiation shielding glasses.

Effects of waste glass addition on the physical and mechanical properties of brick

The use of industrial and municipal wastes to develop sustainable construction and building materials plays a significant role to improve the environment and economy by preserving natural resources and reducing waste management costs. Recycling also helps to reduce land, water, and air pollution as well as waste landfilling issues. The present work has been done to explore the prospect of partial replacement of natural soil for brick manufacturing with municipal waste, which is soda-lime glass. In this study, the effect of waste glass additives on the physical and mechanical properties of brick has been investigated. Bricks were manufactured using 2%, 4%, 10%, 16%, 30%, and 40% of waste glass replacing natural clay. Compressive strength, water absorption, and other tests were carried out to determine the mechanical performance and durability of the prepared brick specimens. An increase in compressive strength and decrease in water absorption of the samples were observed with the addition of waste glass. It was found that the developed bricks have been satisfying the parameters of the Grade-A and Grade-S brick in accordance with the Bangladeshi standard for conventional building clay brick (BDS 208). Results obtained from this study indicated that partial replacement of natural clay in brick with waste soda-lime glass makes the brick production sustainable and eco-friendly.

Radiological parameters of bismuth oxide glasses using the Phy-X/PSD software

Radiation physics and dosimetry have recently been very popular in physics due to their extended utilizations in different scientific studies. This is important for radiation protection issues, particularly for gamma rays, as their shielding is more difficult than that of other radiation types. The radiation-shielding properties of any materials may be obtained by experimental work, but mostly, it is easy to predict these by using simulation codes. Monte Carlo simulation is a good way to predict some parameters, particularly when it is impossible to perform an experiment. Besides other materials, glasses are interesting materials, and it is vital to investigate their radiation-shielding properties. In the present study, some radiological parameters such as linear attenuation coefficients, mass attenuation coefficients, mean free path, half-value length, tenth value length, effective atomic number (Z eff), electron density (N eff), equivalent atomic number (Z eq), exposure build-up factor and fast neutron removal cross-section were calculated using the Phy-X/PSD code for waste soda–lime–silica-based glasses.

Effect of soda-lime glass powder on alkali-activated binders: Rheology, strength and microstructure characterization

Alkali-activated binders (AABs) have the potential to consume various types of cementitious waste materials, including coal ashes, municipal solid waste incinerator ash, palm-oil fuel ash, steel slags, mine tailings, cement kiln dust, ceramic tile residue, rice husk ash, and waste glass. This paper presents a study of alkali-activated cement paste produced with the substitution of the cementitious waste material soda-lime glass, which makes up the major proportion of the general glass waste stream. In the alkali-activated cement paste, crushed soda-lime glass powder (CG) was used as a replacement for class F fly ash (FA) from 0 to 30% by total solid weight, keeping the ground granulated blast furnace slag (GGBFS) content constant at 50%. The influence of activator molarity (4–8 M), alkaline liquid/solid binder (L/S) ratio (0.4–0.5) and different curing conditions (ambient air curing, wet curing, and short-term heat curing) on the rheology, strength, and microstructure of CG-substituted AABs was investigated and optimum conditions are suggested. According to the experimental results, both the workability and strength (compressive and tensile) of the AAB gradually increased with increasing level of substitution of FA by CG. Significant improvement in flow and setting time was seen with the addition of CG, even in mixtures with a low L/S ratio of 0.4. Both ambient and wet curing had more influence on the strength gain of AABs, especially after 28 days. Short-term heat curing resulted in high early strength gain. The dissolution of CG increased with increasing molarity (from 4 to 8 M) of the alkaline solution, which improved both strength and microstructure with curing time. Morphological and elemental analysis indicated an improvement of the microstructure of AABs due to the increased formation of calcium-dominant hydration products and hence reduced porosity with the substitution of CG. However, undissolved large-sized CG particles agglomerated in the binder without participating in the alkaline reactions. These agglomerated particles may induce micro-cracks due to weak bonding between the cement matrix and the smooth CG interface, which reduces the durability of AABs. Therefore, the inclusion of waste soda-lime glass powder with a mean diameter of 10–15 µm as a precursor in FA/GGBFS-based AAB as a replacement for FA is feasible and provides a good solution for waste material recycling.

Physico-mechanical characterization of sintered glass-ceramics fabricated from iron oxide added waste soda lime glasses

This study aims to highlight the sinter-crystallization behavior and mechanical properties of the glass-ceramics prepared from modified soda lime waste glass. To this purpose, different amounts of iron oxide (Fe2O3) (5-15 weight ratio) were added to the soda lime waste glass. The obtained mixtures were then melted and transformed into the glass-ceramics after a one-step sinter/crystallization heat treatment. According to the obtained results, wollastonite (CaO.SiO2) and diopside (CaO.MgO.2SiO2) precipitated in the sintered specimens, simultaneously or separately, depending on the content of iron oxide. On the basis of dilatometry analysis and the Huggins-Sun measurements, addition of iron oxide into the glass composition and its further addition increased the number of non-bridging oxygens and consequently decreased the glass viscosity. The glass-ceramics sintered at 850 °C showed the negligible water absorption and considerable content of the precipitated crystalline phases. Among them, the glass-ceramic Base-10F (containing 10 weight ratio of iron oxide) was considered as the most promising specimen due to its high mechanical strength (96 MPa), Vickers micro-hardness (491 VHN) and near zero water absorption.