Sodium Silicate Research Articles

Soil Improvement by Electrokinetic Sodium Silicate Injection into a Sand Formation Containing Fine Grains

Soil Improvement by Electrokinetic Sodium Silicate Injection into a Sand Formation Containing Fine Grains

A hybrid approach to oil structuring - combining wax oleogels and capillary suspensions.

There is continuing interest in finding new approaches to gel liquid oil for processed food applications. Here, we combined oleogels and capillary suspensions to generate model oil-continuous networks consisting of a wax oleogel and a water-bridged, glass particle network. The composition map tested comprised 30 vol% polar or non-polar glass beads dispersed in a 70 vol% non-particle phase consisting of water (≤9 vol%) as well as 2 wt% hexatriacontane as oleogelator in canola oil. While the hexatriacontane wax alone gelled the oil, presence of the glass beads (but no water) prevented oleogelation. Self-supporting capillary networks formed with polar particles and 1 vol% water or non-polar glass beads and 3 vol% water in canola oil. The capillary suspensions demonstrated significant differences in rheological behaviour as the polar particles yielded much higher elastic moduli than their non-polar particle counterparts. Polar hybrids were weakened by inclusion of the wax whereas the non-polar particle hybrid network displayed elastic moduli greater than the respective contributions of both capillary and wax gel networks. This hybrid method of oleogelation can be applied to virtually any food particles and uses minimal water and wax.

Facile fabrication of next-generation sustainable brick and mortar through geopolymerization of construction debris

Waste from construction and demolition (also known as CDW) is one of the most harmful environmental issues. This study's primary goal is to produce new mortar and brick materials from recycled concrete powder (RCP) and recycled brick powder (RBP), two of the most popular CDW. Geopolymeric mortar and brick samples were produced by passing RCP and RBP through sieve No. 50 (with sand filler if necessary) and combining them with an alkaline solution made of water glass (WG) and NaOH. In this study, the mixture was then cured for three days at 80 °C in an oven. The effects of filler, RBP amount, WG amount, and the concentration of NaOH alkaline solution on the samples’ strength were examined. Additionally, XRF and SEM/XRD tests were performed to verify the materials' composition and microstructure. The mechanical strength of the samples showed an increase with the increase of RCP values, so the brick sample with filler showed the highest compressive strength, measuring 59.53 MPa. The study's samples exhibited strong mechanical properties. Additionally, all of the bricks' water absorption fell within the standard range. In summary, according to different standards, both waste concrete and waste brick can be used to produce geopolymer materials especially bricks for construction and paving purposes.

Influence of geometric shape, pore structure and surface modification of recycled fine aggregate on the rheology behaviour and strength development of mortar

The complex physical properties of recycled fine aggregate affect the rheological and mechanical properties of mortar, thereby limiting its application in cement-based materials. This paper evaluated the geometric shape and pore structure of natural fine aggregate (NFA), recycled fine aggregate (RFA), and recycled fine aggregate modified by water glass (MRFA), and studied its water absorption and bulk density. The influence of complex physical properties of RFA before and after modification on the rheological behavior, strength development, and microscopic properties of mortar was analyzed. The rheological tests were carried out on the fresh mortar with 7 mixes, and the compressive strength and flexural strength of hardened mortar after curing for 3, 7 and 28 days were tested. The results shown that the modification of water glass has improved the water absorption and geometric shape of RFA to some extent, resulting in a small increase in the apparent viscosity and yield stress of recycled mortar compared to NFA mortar. When the replacement level of RFA was less than 30 %, the compressive strength of recycled mortar was 13 % higher than that of NFA mortar. As the replacement level increased to 40 %, the incorporation of water glass also helped to improve the mortar strength. The irregular geometric shape and high water absorption of RFA were conducive to achieving dense mechanical bonding and reducing the Ca/Si ratio in the interface transition zone.

Martian Regolith Simulant-Based Geopolymers with Lithium Hydroxide Alkaline Activator

As humanity envisions the possibility of inhabiting Mars in the future, the imperative for survival in the face of its challenging conditions necessitates the construction of protective shelters to mitigate the effects of radiation exposure and the absence of atmospheric pressure. The feasibility of producing geopolymers using the Martian regolith simulant MGS-1 (as precursor) for potential building and infrastructure projects on Mars in the future is investigated in this paper. Various alkaline activators, such as sodium hydroxide (NaOH), lithium hydroxide (LiOH·H2O) and sodium silicate (Na2SiO3), are employed to investigate their efficiency in activating the precursor. The influence of alkali type and concentration on the mechanical performance of the synthesized geopolymers is examined. Geopolymer samples are oven-cured for 7 days at 70 °C before a compressive strength test. It is found that through the hybrid use of LiOH·H2O and NaOH with optimal concentrations, metakaolin and milled MGS-1 as precursors, geopolymer mixtures with a compressive strength of 30 ± 2 MPa can be developed. The present test results preliminarily demonstrate the potential of Martian regolith simulant-based geopolymers as suitable construction and building materials for use on Mars.

Effect of water glass treatment for zirconia and silane coupling on bond strength of resin cement.

To evaluate the ability of the water glass treatment to penetrate zirconia and improve the bond strength of resin cement. Water glass was applied to zirconia specimens, which were then sintered. The specimens were divided into water-glass-treated and untreated zirconia (control) groups. The surface properties of the water-glass-treated specimens were evaluated using surface roughness and electron probe micro-analyser (EPMA) analysis. A resin cement was used to evaluate the tensile bond strength, with2 and without a silane-containing primer. After 24h in water storage at 37°C and thermal cycling, the bond strengths were statistically evaluated with t-test, and the fracture surfaces were observed using SEM. The water glass treatment slightly increased the surface roughness of the zirconia specimens, and the EPMA analysis detected the water glass penetration to be 50μm below the zirconia surface. The application of primer improved the tensile bond strength in all groups. After 24h, the water-glass-treated zirconia exhibited a tensile strength of 24.8 ± 5.5MPa, which was significantly higher than that of the control zirconia (17.6 ± 3.5MPa) (p < 0.05). After thermal cycling, the water-glass-treated zirconia showed significantly higher tensile strength than the control zirconia. The fracture surface morphology was mainly an adhesive pattern, whereas resin cement residue was occasionally detected on the water-glass-treated zirconia surfaces. The water glass treatment resulted in the formation of a stable silica phase on the zirconia surface. This process enabled silane coupling to the zirconia and improved the adhesion of the resin cement.

Evolutionary Algorithms for Strength Prediction of Geopolymer Concrete

Geopolymer concrete (GPC) serves as a sustainable substitute for conventional concrete by employing alternative cementitious materials such as fly ash (FA) instead of ordinary Portland cement (OPC), contributing to environmental and durability benefits. To increase the rate of utilization of FA in the construction industry, distinctive characteristics of two machine learning (ML) methods, namely, gene expression programming (GEP) and multi-expression programming (MEP), were utilized in this study to propose precise prediction models for the compressive strength and split tensile strength of GPC comprising FA as a binder. A comprehensive database was collated, which comprised 301 compressive strength and 96 split tensile strength results. Seven distinct input variables were employed for the modeling purpose, i.e., FA, sodium hydroxide, sodium silicate, water, superplasticizer, and fine and coarse aggregates contents. The performance of the developed models was assessed via numerous statistical metrics and absolute error plots. In addition, a parametric analysis of the finalized models was performed to validate the prediction ability and accuracy of the finalized models. The GEP-based prediction models exhibited better performance, accuracy, and generalization capability compared with the MEP-based models in this study. The GEP-based models demonstrated higher correlation coefficients (R) for predicting the compressive and split tensile strengths, with the values of 0.89 and 0.87, respectively, compared with the MEP-based models, which yielded the R values of 0.76 and 0.73, respectively. The mean absolute errors for the GEP- and MEP-based models for predicting the compressive strength were 5.09 MPa and 6.78 MPa, respectively, while those for the split tensile strengths were 0.42 MPa and 0.51 MPa, respectively. The finalized models offered simple mathematical formulations using the GEP and Python code-based formulations from MEP for predicting the compressive and tensile strengths of GPC. The developed models indicated practical application potential in optimizing geopolymer mix designs. This research work contributes to the ongoing efforts in advancing ML applications in the construction industry, highlighting the importance of sustainable materials for the future.

Immobilization properties and reaction mechanism of municipal solid waste incineration fly ash with alkali activation technology

Municipal solid waste incineration fly ash (MSWIFA) needs proper treatment prior to security landfilling because of considerable amounts of heavy metals and soluble chloride. Nowadays, alkali activation technology has become an effective solidification/stabilization (S/S) technology for MSWIFA. But few studies have been systematically carried out on the preparation techniques and reaction mechanism of MSWIFA S/S body. The effects of the technical parameters (alkali activator, sodium silicate modulus, alkali equivalent, water-solid ratio, curing regime) on the immobilization properties (compressive strength and heavy metal leaching toxicity) of MSWIFA S/S bodies were studied in this work. The hydration characteristics and reaction mechanism were also explored in depth based on the structure properties and microstructure characterization. Ca2+, Na+, SiO42−, [Al(OH)4]-, OH− dissociated from MSWIFA and alkali activator solution chemical reaction to form the silicates, aluminates and aluminosilicates with lower polymerization, and promoted the gel hydration products formation via depolycondensation. Lower Ca/Si molar ratio was conductive to the formation of amorphous substance, compactness of matrix pore structure and immobilization properties. Compared to the hydration products including halite, sylvine, glauberite, gypsum, calcite crystal, C–S–H gel contributed much more to the pore structure and strength improvement of MSWIFA S/S bodies. These findings will provide valuable theoretical basis for MSWIFA management and resource utilization promotion.

Achieving sustainable and highly efficient wood bonding through synergistic plant root-driven penetration mode with a hyperactive interface

Wood adhesives are widely used in furniture manufacturing, the construction industry, and the fabrication of the internal components of aircraft, cars, and sports equipment. Therefore, the development of wooden adhesives with high stability, strength, and efficiency is a vital research area. Although most studies have focused on improving the bonding properties of adhesives, achieving direct interface control from wood remains a challenge. This study was designed based on the plant root-driven adhesion method to create a hyperactive-interface self-driven regulated wood capable of spreading adhesive into the wood and inducing crosslinking to improve adhesive strength. A multi-poly silicate network structure with multiple reactive sites was formed through the self-polymerization of sodium silicate and crosslinking with dimethylol dihydroxy ethylene urea (DMDHEU) to achieve densified wood and improve the reactivity of the wood surface and interior. Consequently, the environmentally friendly polyvinyl acetate (PVAc) underwent a self-driven bonding process with the wood. These findings indicate that PVAc penetrated the interior of the wood, disrupting the combination of sodium silicate and DMDHEU and grafting onto the reactive sites. This process resulted in a tightly bonded interface connection. Consequently, the shear strength increased from 4.4 to 5.5 MPa, and the wood breaking rate increased from 21.00 % to 45.80 %, representing a 25 % and 118.10 % increase, respectively. Moreover, the tensile strength of the wood in longitudinal joints, transverse joints, miter joints, and mortise–tenon joints was assessed. The results revealed that the sodium silicate/DMDHEU-regulated wood (SS/DDRW) exhibited significantly higher adhesive strength than the original wood (OW). Hence, this bionic design represents a simple and efficient strategy for developing wood adhesives.

SYNTHESIS AND CHARACTERIZATION OF PURE AMORPHOUS SILICON OXIDE FROM TREATED KAOLINITIC CLAY USING CHEMICAL EXTRACTION

Pure silicon oxide was produced in this study utilizing a sodium silicate solution made from Kankara clay as a precursor. The Kankara clay that was obtained from Nigeria was first beneficiated to produce pure dried powder clay. After that, the dried powdered clay was treated with heat activation and acid leaching, respectively. In a 500 mL Erlenmeyer flask, appropriate amounts of each clay (raw, thermally treated clay, and leached clay) were reacted with 3M NaOH solution. The flask was heated to 200°C and stirred continuously for 3 hours on a magnetic stirring hot plate connected to a reflux condenser. The solution was filtered to yield sodium silicate solution, which was then precipitated with 3M HCl while constantly stirring to produce a gelly-like white substance. The gel was aged for 18 hours, then washed with de-ionized water several times before being dried at 80°C for 12 hours to get pure white silica particles, which were subsequently described. The XRD analysis revealed that the silicon oxide synthesized is amorphous, but the microstructure evaluation revealed particles aggregation, which is usual in sol-gel synthesized powder.

Tailoring porosity and acoustic properties in bi-layered diatomite-based foams through multiscale structural approach

A tailored multifunctional diatomite-based foam with porosity and density gradients has been developed through a new technology that enables an unprecedented integration of acoustic, mechanical and thermal properties. The production process consists of a custom-made pilot plant for foaming capable of mixing solid phases, such as diatomite, catalyst and silicon chemical blowing agent, with a liquid solution, made of sodium silicate cross-linking agent and vegetable foaming agent. The resulting foam exhibits a coin-like performance, with a side A showing an open cell morphology, high interconnectivity and low density, and a side B characterized by a partially open cells morphology, low interconnectivity and high density. This approach enables morphology and density to be layered along thickness. A transition zone with intermediate density and morphology separates the two sides, thus rendering the structure a gradient meta-material with hierarchical porosity. Macro- and micro-porosity are generated by physical and chemical foaming agents, while diatomite is responsible for the presence of nanoporosity. The gradient structure has a huge influence on functional properties, such as acoustic (α equal to 0.95 at 800 Hz for side A), thermal (thermal conductivity less than 0.061 W/(m·K) for side A and less than 0.12 W/(m·K) for side B) and mechanical properties.

Synthesis of solid sodium silicate from waste glass and utilization on one-part alkali-activated materials based on spent oil filtering earth.

Alkali activated materials (AAMs) commonly known as geopolymers are considered ecofriendly substitutes for Portland cement. However, these materials still have a significant environmental impact, owing mainly to the use of activators based on commercial chemical products. In this sense, this research focuses on the production and use of waste glass-derived activators AAMs as an alternative to commercial activators. Using a thermochemical synthesis method, activator compositions were systematically designed to achieve predefined activator modulus (Ms = SiO2/Na2O = 0.5; 1.0 and 1.5). These alternative activators were studied by XRD, FTIR and SEM techniques. Additionally, one-part AAMs were manufactured using spent oil filtration earth (SOFE) as precursor and activator with optimum modulus Ms = 1.0. The influence of the Na2O dosage was studied (10; 20 and 30g of Na2O per every 100g of SOFE) as well as the influence of the activator modulus maintaining the optimum dosage of 20g Na2O per 100g of SOFE. As a control, two-part AAMs were also synthetized with the optimum dosage and modulus employing commercial activators (NaOH + Na2SiO3 solution). Results indicate that the modulus of the alternative activator and especially the Na2O dosage have a significant influence on the technological properties of AAMs based in SOFE, with an optimum compressive strength (35.8MPa) for the addition of 20g of Na2O per every 100g of SOFE using activator with modulus Ms = 1.0. This research embodies a sustainable approach to AAM production and suggests waste glass as a valuable raw material for sodium silicate synthesis intended for the one-part activation of spent filtering earth from the agri-food industry, aligning with the principles of circular economy and sustainable development goals.

Study on the Characteristics and Mechanism of Shield Tunnel Mud Cake Disintegration in Complex Red-Bed Geology

The complex red-bed geology is primarily composed of iron-rich sedimentary rock layers with clay minerals as a major component. The soil water content exceeds 30%, and its high viscosity and water content lead to the easy formation of mud cake on the cutterhead, endangering the safety and progress of construction, which poses a significant challenge for tunnel boring machines (TBMs). The use of dispersants to eliminate mud cake is a common method in engineering projects. This paper presents an improved disintegration experiment instrument to study the disintegration characteristics of mud cake from the red-bed geology under different dispersant solutions, proposing a dispersant formulation suitable for the red-bed geology of the Haizhu Bay Tunnel project. The results indicate that mud cake samples exhibit a moderate disintegration effect in pure water. Furthermore, it has been observed that the disintegration effect decreases as the thickness of mud cake increases. Sodium silicate solution was not suitable for treating the red-bed geological mud cake, while sodium hexametaphosphate and oxalic acid solutions had a good promoting effect on the disintegration of red-bed geological mud cake. However, there was a threshold for the dispersant concentration; exceeding this threshold actually worsened the disintegration effect. Ultimately, the engineering application of a 10% oxalic acid solution, which proved effective in disintegrating the mud cake, significantly enhanced the excavation efficiency in the Haizhu Bay Tunnel project.

Development of geopolymer mortar made from bagasse ash with waste aluminum

Geopolymer concrete is a type of concrete that is produced using industrial waste materials such as fly ash, slag, and other similar materials instead of traditional Portland cement. This research studied the variables affecting geopolymer mortar from bagasse ash mixed with aluminum scraps. The waste materials, bagasse ash (BA) and aluminium scrap (AL) were crushed to reduce the particles by grinding. An amount of ALU 0.01 – 0.15 wt% bagasse (BA) ash was added to the mixture. The alkaline solutions (AS) used to leach silicon oxide and aluminium oxide from BA were sodium hydroxide (NH) and sodium silicate (NS). The concentration of NH solution was varied between 7.5 – 15 molar. The ratio of alkaline solution to bagasse ash (AS/BA) was controlled at 0.50. Mortar samples were cast and cured at 60 80 and 100 °C for 48 hours. The results showed that the 10-molar sodium hydroxide solution tended to support the higher compressive strength. The highest compressive strength of geopolymer was found when using 0.04% aluminum scrap and curing at 80 °C. The additional water improved the workability of the fresh mortar, but the lower strength of the geopolymers was archived. GRAPHICAL ABSTRACT HIGHLIGHTS Do not use as a cementitious binder Reuse waste materials It is an environmentally friendly and sustainable material

Valorization of aplite in alkali-activated materials

Geopolymers belong to the broad family of alkali-activated materials that are considered to have much smaller carbon dioxide (CO2) footprint than traditional Portland cements. A wide range of metallurgical wastes are utilized as silicious sources to produce geopolymer components with a prospect of numerous applications in the construction field. At the same time, efforts have been also made to the valorization of aplite rock, which is found to be abundant in Finnvolldalen of Norway and consists mainly of quartz and alkali feldspar, resembling the composition of Na-rich pozzolans. In this framework, the current study focuses on the synthesis of inorganic polymers made of aplite and metakaolin as precursors. In addition, the production of synthetic Na-waterglass is also tested as candidate soluble silica donor in geopolymer systems, through the hydrothermal treatment of aplite. The obtained results confirm that inorganic polymers produced by hydrothermally treated aplite (HTA) and metakaolin (MK) lead to materials with enhanced compressive strength values compared to specimens produced by untreated aplite and MK. At the same time, sodium silicate solution from aplite and commercially available waterglass present similar properties, indicating that aplite can be used as alternative raw material in the production of sodium silicates.

Towards sustainable construction: Performance evaluation of slag-cenosphere geopolymers under different NaOH concentrations

The incorporation of industrial wastes into construction materials, such as geopolymers, is highly desirable to improve their environmental impact. The choice of source materials, such as slag and cenosphere, and the amount of activator used significantly impact the properties of geopolymers. For instance, including high-reactivity precursors and optimizing activator composition may enhance mechanical strength and durability. However, no studies have evaluated the effect of cenosphere addition on the properties of geopolymer composites. This research study aims to unveil the synthesis of a binary geopolymer material by integrating slag and cenosphere as precursors, activated by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Geopolymer composites were prepared to assess the impact of cenosphere addition (by substituting the slag with cenosphere in different percentages of 25, 50, and 75 %) and NaOH concentration (specifically 6 M, 9 M, and 12 M) on the material's properties. Additionally, one conventional mortar with a water-to-cement ratio of 0.5 was also prepared. Compressive strength, ultrasonic pulse velocity (UPV), electrical resistivity, water absorption, density, and thermogravimetric analysis were conducted. Results showed that increasing the cenosphere percentage increased the water absorption and decreased the compressive strength, UPV, electrical resistivity, and density compared to the geopolymer mixture with 100 % slag content. However, up to 50 % substitution of cenosphere, the geopolymer mix performed better than conventional mortar. Notably, results suggest a potential increase in CO2 uptake due to the addition of cenosphere, further enhancing the environmental performance of geopolymer composites. The findings of this study suggest the potential use of slag-cenosphere geopolymer as an alternative and sustainable construction material.

Effect of activator concentration on setting time, workability and compressive strength of sustainable concrete with alkali-activated slag binder

The global need to reduce carbon dioxide (CO2) emissions prompted studies on sustainable alternatives to conventional concrete made with ordinary Portland cement (OPC) binders. Alkali-activated ground granulated blast furnace slag (GGBS) is a promising sustainable to OPC in terms of the impact on the environment and reduction of CO2 emissions. Concretes and mortars made with alkali-activated binders demonstrate promising fresh and mechanical properties. This article presents the findings of an experimental study investigating the fresh and mechanical properties of mortar using alkali-activated GGBS binder. The activators used were sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solution with 6 M, 8 M, 10 M, and 12 M molarities. The study assessed their initial setting time, workability, and 28-day compressive strength. The study evaluated the effect of partial replacement of GGBS with 5 % silica fume. The compressive strength was determined after 28 days of curing in three different environments: 1) ambient air temperature, 2) water submersion, and 3) water immersion for 7 days followed by 21 air curing in ambient temperature. The results showed an increase in compressive strength with higher NaOH concentration but a corresponding decrease in initial setting time and flowability. Depending on the curing method, efflorescence, and blue-green pigmentation were seen during the physical assessment of the samples. The highest 28-day compressive strength was 67.5 MPa when the NaOH activator molarity was 10 mol/L which represents an optimum concentration for strength development. Replacing 5 % of the GGBS binder with silica fume resulted in a decrease in the 28-day compressive strength and workability without affecting the initial setting time.

Preparation and evaluation of GCD-1 lunar regolith simulant based geopolymer activated by solid sodium silicate

In this study, a new lunar regolith simulant, named "GCD-1", was formulated by combining various minerals, such as anorthite, albite, pyroxene, ilmenite, slag, and fly ash. Through X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) analysis, it was verified that the main mineral composition of GCD-1 was basically the same as that of the lunar soil at the Apollo 14 landing site, in which the deviation in the main compound (i.e., SiO2 and Al2O3) was within 0.5%. Furthermore, GCD-1 based geopolymer was prepared by the one-part method, which was a mixture of solid GCD-1 precursor, solid sodium silicate (SS) activator, and water. The average daytime temperature at the lunar equator, which was calculated to be 60°C, was set as the curing temperature for the GCD-1 based geopolymer. The strength development of the GCD-1 based geopolymer was then characterized by unconfined compressive strength (UCS) for 3, 7, and 12 curing days to consider the effectiveness of the factors (solid SS to lunar regolith simulant [S/L] and water to binder ratio [W/B]). The micro-analysis tests including scanning electron microscope-energy dispersive spectrometer (SEM-EDS), mercury intrusion porosimetry (MIP), and brunner-emmet-teller (BET), were further conducted to investigate the microstructural development of the GCD-1 based geopolymer. Results showed that the increase of the W/B ratio in the GCD-1 based geopolymer tended to increase the total porosity of the sample, thereby inducing a lower UCS. At the same time, for a fixed W/B ratio, the higher S/L ratio had a certain inhibition effect on the hydration reaction, which caused the reduction in the UCS of the sample. The highest UCS of the GCD-1 based geopolymer reaching 30.54MPa, was achieved under the simulated lunar equatorial daytime temperature for 12 days with W/B and S/L ratios set at 0.25 and 0.18, respectively. Microstructure and mineralogy analyses indicated that the hydrated sodium aluminosilicate (N-A-S-H) gels contributed to reducing the sample's porosity, thereby enhancing the UCS. The relationship between the UCS and total porosity of GCD-1 based geopolymer was then derived. The results of the current study are crucial for lunar base construction with in-situ resources.

CERVUS ELAPHUS: CULTIVATION IN THE KALININGRAD REGION, PROCESSING AND EVALUATION OF THE QUALITY AND SAFETY OF VENISON PRODUCTS

Recently, there has appeared a tendency to use non-traditional animal raw materials to expand the range of sausages. The purpose of the research is to determine the organoleptic and physico-chemical properties, as well as quality indicators of new sausages with a mass fraction of deer muscle tissue in the recipe (&gt; 60%). An organoleptic evaluation was carried out, then the study of physicochemical parameters, the mass fraction of protein, fat, salt, sodium nitrite, total phosphorus, and residual activity of acid phosphatase was performed. Next there were studied such microbiological indicators as QMAFAnM, BGKP (coliforms), sulfite-reducing clostridia, Staphylococcus aureus, and pathogenic microorganisms: Salmonella, Escherichia coli, Listeria monocytogenes. Safety indicators have been established: the content of toxic elements (mercury, arsenic, cadmium, lead) and quality indicators: the content of nitrosamines, pesticides. The quality control of packaging and labeling was carried out visually in accordance with the requirements of the standard. The temperature is measured inside the product with a glass liquid thermometer. The net weight of consumer packaging was determined gravimetrically by static weighing. It has been proved that all three types of the studied sausages «Zavtrak okhotnika», «Drezdenskiye» and «Oldenburgskiye» corresponded to the normative documentation in terms of organoleptic, physico-chemical properties, quality and safety indicators, nutritional value.

Critical evaluation of effects of polymer concentrations on the set time and compressive strength of cement slurries

Thickening time and compressive strength of cement slurry are very critical parameters in well cementing. Thickening or pump time and compressive strength of cement slurries are greatly affected by the slurry weight and temperature. Conventional Lead slurries usually require extenders such as bentonite and some polymers to stabilize the slurry and minimize excessive free fluid. The low slurry weight of lead slurries usually give rise to long pumping or set time and low compressive strength. Some of the polymers also retard the setting of the cement slurry. Therefore, this study focuses on the investigation of the performance of sodium silicate in comparison with gypsum and polyanionic cellulose (PAC-R) as extenders for cement slurries. The concentration of the light weight additives tested were 0%, 1.5% and 3.0% by weight of cement (bwoc) for 12.5ppg slurry using sea water. The slurry stability, compressive strength and quick set time were determined at room temperature. The higher the concentration of the lightweight additives, the more stable is the slurry, best stability was observed for recipe with sodium silicate while the slurry with PAC-R could not mix at 3% bwoc. At the lower concentrations, for sodium silicate, compressive increases and decreases for gypsum. The mixture with PAC-R had zero compressive strength. The gypsum has retarding effect on the slurry while the sodium silicate has accelerating effect. Conclusively, sodium silicate and gypsum powder performed very well as cement extender at optimum concentration, with the former showing the best performance and impacting accelerating properties that will be useful fort low temperature cementing.