Reduced Water Absorption Research Articles

Calcium ion regulation of sodium alginate in pure buckwheat noodles shown by in vitro simulated digestion.

The effects of calcium sodium alginate on quality and starch digestion of pure buckwheat noodles were investigated. The incorporation of calcium ions into noodles containing sodium alginate was found to reduce water absorption by the noodles during cooking, together with an increase of the turbidity. Calcium addition improved the noodle texture, as shown by the measurement of hardness, elasticity, adhesion, and chewability. In vitro simulations of digestion showed that calcium ion cross-linking with sodium alginate reduced glucose formation by approximately 23.3 mg/g. X-ray diffraction and Fourier transform infrared spectroscopy showed alterations in the crystal zone of the noodles induced by an alginate gel network, although no new chemical substances were generated. Noodles prepared by this exogenous method may be useful as functional foods for patients with diabetes.

Treatment of material surfaces with bacterial solutions to initiate the deposition of calcium carbonate. Review

Introduction. Surface treatment plays an important role in protecting decorative stone and concrete from the effects of harmful environmental factors. To protect stone surfaces, dietary supplements in the form of carbonatogenic bacteria, the product of which is calcium carbonate, can be used.Materials and methods. The selection and analysis of publications containing the results of research and experiments, which allow to draw conclusions about the feasibility of using bacterial solutions for surface treatment, has been carried out.Conclusions. The formation of a layer of calcium carbonate on the surface of the material reduces gas permeability, reduces water absorption, increasing the durability of concrete. It was found that the surface treatment of cement stone with solutions containing cultures of urobacteria strengthens the surface layer of the stone, but does not restore its strength. It is important that the formed layer of calcium carbonate on the surface of the material does not clog its pores. The chemical and structural similarity between the processed material and the resulting carbonate compounds must be observed. The dosage of urea and calcium chloride should correspond to the number of bacterial cells, since excess components of the nutrient medium leads to their accumulation in the pores.

Development of Fiber Reinforced Sustainable Dredge Bricks

To maintain adequate depth of commercial waterways, large quantities of earthen material are dredged and stored on undeveloped placement areas adjacent to the waterway. As dredge placement areas become overwhelmed, an environmental and financial sustainable solution for the reuse of dredged soil is prioritized. In this study, locally dredged material from the Sabine-Neches Waterway was used to explore the potential of dredged material in the production of compressed stabilized earth bricks (CSEBs) for small-scale structures in the region. CSEB mixture designs were developed containing fly ash (FA), Portland cement (PC), hydrated lime (HL), water (W), dredged material (DM), and natural and synthetic fibers. Optimized mixtures designs reached the recommended compressive strength of over 1200 psi. Results showed that that the addition of fibers reduced the compressive and flexural strength of the bricks, with a maximum compressive strength of 1394 psi with a corresponding flexural strength of 381 psi being obtained with fiberless dredge bricks. Multiple coating systems were also tested to increase the resistance of the bricks to weathering and erosion. Results showed that the use of coatings reduced water absorption and increased the bricks resistance to erosion, making them more adept in regions commonly subjected to flooding and heavy wind-driven rains.

Multifunctional silane-based superhydrophobic/impregnation treatments for concrete producing C-S-H gel: Validation on mockup specimens from European heritage structures

Many of the concrete structures that conform our modern cultural heritage are in need of repair and protective interventions. Silane-based impregnation treatments can be used to repair onset cracks and reinforce the surface due to their ability to produce silica and C-S-H gels, and can be modified by incorporating hydrophobic precursors to create multifunctional treatments that also protect from water ingress.Since the effectiveness of impregnation treatments is dependent on substrate properties and chemical-physical changes it may have experienced over time, validation using standard materials may not always be representative of on-site application. In this work, the effectiveness of three innovative silane-based impregnation treatments developed by our group (two of them combining superhydrophobic properties) was evaluated on mockup specimens, which simulate the properties of the cementitious materials from six different heritage structures across Europe, artificially aged to simulate weathering by three methods: carbonation, chloride ingress and physical damages (freeze–thaw and thermal cycles).The characterization of the treatments showed they are compatible in terms of chemical interaction, applicability and minimal aesthetical alterations. Surface resistance and ultrasound pulse measurements have been used to assess the improvement in mechanical properties. The incorporation of hydrophobic components and fumed silica has a relatively low impact over the mechanical properties while it significantly reduces water absorption and grants water repellent properties to the surface, giving rise to a superhydrophobic performance.

Biomineralização de carbonato de cálcio no concreto pela ação do Bacillus pumilus

ABSTRACT The present study evaluated the viability of the bacterium Bacillus pumilus as a biological agent in the process of calcium carbonate precipitation on a concrete surface. This evaluation was carried out in a curing tank of concrete samples, applying a nutrient solution enriched with B. pumilus for 48 h. During the experimental period, a urease test was performed to determine whether the microorganisms could hydrolyze urea by the action of the urease enzyme. The results revealed that B. pumilus is susceptible to converting urea into ammonium and increasing the medium pH. There was also a 0.03 g cm-2 reduction in water absorption by capillarity in specimens biomineralized with B. pumilus compared to conventional specimens. Due to the degree of surface protection, microorganisms have reduced the material’s porosity, causing an increase in tensile strength by diametric compression of approximately 9.0 MPa. The lower height of capillary rise observed was 1.83 cm in biomineralized specimens and 3.83 cm for conventional specimens. The results obtained with the scanning electron microscope and energy dispersive spectroscopy indicate the presence of CaCO3 precipitated by the bacteria. In general, the results obtained in this study show that B. pumilus may improve its mechanical properties when it is applied superficially to concrete.

Processing of natural lignocellulosic coir fibres for enhanced flame retardancy using aluminium trihydrate

The high lignin cellulose ratio in coir fibres makes it more susceptible to fire, whereby coir and its allied products are pushed back away from fire retardant applications. These fibres are subjected to treatments by soaking in hot dilute solution of aluminium trihydrate for enhanced fire retardancy. The treated fibres exhibited improved flame retardant properties with reduced water absorption and showed no remarkable change on the physical and mechanical characteristics. The time of burning was significantly reduced from 182 to 65 seconds and the treated fibres did not produce smoke when burnt. The flame propagation rate was reduced by 2.5 times and limiting oxygen index elevated by 1.2 times compared to the raw fibre. As a low toxic, sparingly soluble substance, aluminium trihydrate is a better halogen-free fire retardant addition for coir fibres in product manufacturing in the coir sector.

Effect of sugarcane bagasse ash on compressive strength and water absorption of foam concrete using sea sand and seawater

The rapid development of infrastructure has led to a shortage of construction materials. Therefore, the utilization of waste or potential materials is gaining attention. This study aims to investigate the effect of partially replacing Portland cement with sugarcane bagasse ash (SCBA) in Phu Yen province and sea sand-seawater (SSSW) on the properties of foam concrete. Portland cement was replaced with SCBA at 0, 5, 10, and 15% by mass of the binder. The results showed that the compressive strength of foam concrete was reduced at 7 days due to the SCBA replacement. However, the inclusion of 5% and 10% SCBA increased the compressive strength and reduced the water absorption of foam concrete compared to the reference concrete at 91 days. Moreover, the combination of SCBA and SSSW significantly contributed to the enhancement of compressive strength and reduction of water absorption of foam concrete at 91 days, especially when SCBA replacement was less than 10%. In general, the use of SCBA and SSSW is feasible in the production of foam concrete, considering the increasing scarcity of construction materials and the goal of reducing CO2 emissions.

Influence of steel fiber on the water absorption of 3D printed concrete

• Using X-CT combined with CsCl enhancing to study the water transport in hardened 3DPC. • Steel fiber alignment can enhance water uptake rate, compared with molded concrete. • Steel fiber can not elevate the sorptivity of printed concrete along the filament. In this study, X-CT combined with CsCl enhancing method is used to investigate the effect of steel fiber on the unsaturated flow in printed concrete along the printing direction, and to contrast the molded concrete. Results indicate that this method could be used effectively to monitor the evolution of water ingress into cementitious materials continuously. The addition of steel fiber slightly reduces water absorption rate in printed specimens. Compared with the molded specimen, the fiber alignment enhances the sorptivity of the printed specimen significantly.

Increasing the Biostability of Concrete by the Introduction Of Additives

To increase the resistance to fungal corrosion and improve the performance of concrete cement stone, it is proposed to introduce calcium stearate and active metal nitrates in an amount of 0.5% by weight of cement into the cement mixture at the manufacturing stage. To determine the degree of corrosion damage of cement stone by fungal microorganisms Aspergillus niger, porosity, density, water absorption and strength were determined. It has been found that the introduction of a hydrophobic additive of calcium stearate into the cement mixture during the manufacture of concrete reduces water absorption, reduces porosity and increases strength. Additives of nitrates of active metals do not affect the characteristics of the cement stone of concrete. As a result of 6 months of fungal corrosion, the water absorption, porosity and density of cement stone containing calcium stearate did not change, and the strength decreased by 4%. Metal nitrates do not prevent damage to the cement stone by microorganisms, but slow down the flow of aggressive substances to the surface of the reinforcement in concrete. The combined introduction of calcium stearate and nitrates into the cement mixture will improve the characteristics of concrete, increase its corrosion resistance and ensure the safety of reinforcement in concrete.

Effect of Calcite Precipitation on Properties of Fresh and Hardened Laterized Concrete

Reduction in strength and durability is the limitation for use on laterized concrete in various engineering applications.This research focuses on the effect of calcite precipitation on the strength and durability of laterized concrete. The laterized concrete sample was prepared by fine aggregate replacement with laterite at 0 %, 10 %, 20 %, 30 %, and 40 % by weight of fine aggregate. A prescribed concrete mix proportion of 1:1.5:3 and a water-to-cement ratio of 0.5 was used to prepare the concrete. At each level of replacement, Sporosarcina Pasteurii bacteria at concentrations of 0, 1.5 x 108, 3.0 x 108, and 6.0 x 108 cells/ml were incorporated in the laterized concrete. Fresh concrete samples were tested for slump, hardened concrete cubes were tested for Compressive Strength at 7, 14, 21 and 28 days of water curing and a durability test in form water absorption was performed after 28 days. The slump results showed that the workability of the concrete reduces as the laterite content increases due to more water absorption during mixing, however, the concentration of bacteria had no discernible impact on the slump value. The results of the compressive strength test showed that the compressive strength at all bacterial cell concentrations improves with curing age and declines with increasing laterite content. However, the strength of laterized concrete prepared at a 10% level of replacement is marginally similar to the control sample. All the bacterial concrete performed better than their corresponding non-bacterial concrete with 1.5x108 cells/ml giving the optimum result. The water absorption of the samples was found to increase with an increase in laterite content and after the bacteria introduction, the concrete samples showed reduced water absorption when compared with the non-bacterial samples with 1.5 x 108 cells/ml giving the optimum improvement. Calcite crystals and denser surfaces were found by scanning electron microscopy imaging in the bacterial concrete. The bacterial laterized concrete with laterite replacement not exceeding 20% produced concretes of compressive strengths greater than 〖25N/mm〗^2and is suitable for reinforced concrete works

Effect of cementitious capillary crystalline waterproof material on the various transport properties of cracked cementitious composites

The chemical reaction of CCCW endows it with the promise of improving self-healing behavior of crack of cementitious materials. However, there are few relevant studies about the self-healing behavior of CCCW in the different environments. Thus, the effect of CCCW on the various transport properties of cracked cementitious composites was explored in this paper, to clear the potential of CCCW in enhancing the durability recovery of cracked specimens. Four types of engineered cementitious composites (ECC) with various CCCW content were pre-cracked followed by curing in water, Ca(OH)2 solution and air. Water absorption and rapid chloride penetration tests were adopted to evaluate the various transport properties. And the closure behavior of crack was observed by the microscope. The composition and proportion of the self-healing products were analyzed by TG, XRD and FITR. Test results indicated that CCCW can promote the rapid reduction of water absorption of cracked specimens in early healing stage. The reduction range of charge passed of pre-cracked specimen with 4.5 % CCCW content were 8.03 % and 16.27 % higher than those of specimens without CCCW after curing in water and CH solution. CCCW facilitated lowering the various transport properties of cracked specimens, easier to restore to the uncracked state, especially in Ca(OH)2 solution. The healing degree of crack without CCCW with a width of 240.25 μm is only 36.61 %. However, the maximum crack width completely closed increased to 402.82 μm in Ca(OH)2 solution by adding 4.5 % CCCW content. After healing for 14 wet-dry cycles, the content of calcium carbonate in the healing products with CCCW was 12.19 % higher than that without CCCW. The formation of calcium carbonate was accelerated by CCCW in the entire healing process, increasing the number of healing products, thus helping to reduce the transport properties of cracked specimens.

Study on the workability, mechanical property and water absorption of reactive powder concrete

In order to investigate the influence of various factors on working performance, mechanical properties and durability of sustainable Reactive Powder Concrete (RPC), and make it convenient for choose more cost-effective RPC incorporating industrial byproducts. The effective parameters (water-binder ratio, contents of water reducer, replacement ratios of fly ash (FA), silica fume (SF) and slag powder (SL)) of RPCs were examined by the tests of paste fluidity, compressive and flexural strength as well as water absorption. Besides, the effect of the active mineral admixtures on pore size distribution and surface morphology of RPCs was studied by Mercury Injection Porosimeter (MIP) and Scanning electron microscope (SEM). Results indicate that an obvious reduction in the workability of RPC, enhancement of strength, and reduction in water absorption can be achieved by substituting part of the cement with silica fume. Fly ash and slag powder can be used to substitute some cement in producing RPC, and the workability is improved, meanwhile the effect of fly ash is higher than that of slag powder. However, excessive replacement of cement with slag powder or fly ash leads to a reduction of the strength in the early stage and a greater absorption of water. Increment of curing age is associated with an enhancement of strength and a decrease in water absorption. The porosity is reduced by 5.2 % when cement is partially replaced with silica fume, and the microstructure is dominated by harmless pores. When replacement of silica fume is kept at 25 %, using slag powder or fly ash substitute part of cement also reduces the number of less harmful pores. It is beneficial to add slag powder to increase the number of gel pores, whereas fly ash reduces the number of gel pores. RPC can achieve a high strength, low water absorption, and improved economy and environmental protection when silica fume replaces up to 25 % cement, slag powder or fly ash replaces up to 30 % cement. This investigation is expected to provide a practical method in the mix design and engineering application of economical and sustainable RPC.

Wet dyeing sludge being pelleted and introduce d in clay brick production to promote product quality and sludge consumption dosage

The introduction of dyeing sludge in the production of fired brick is an economic and practical disposal approach. However, wet dyeing sludge is easy to form block mass during the mixing process of raw materials due to the high moisture content, which affected the production efficiency and destroyed the homogeneous structure of the fired brick, posing a negative impact on the engineering performance of the fired brick. In this study, wet sludge firstly is firstly pelleted and then introduced in the production of fired bricks to reduce the negative impacts on mixing process and the products quality. The results showed that the introduction of dyeing sludge pellets significantly improved the physical and mechanical properties of fired bricks. Compared with bricks incorporating dyeing sludge, water absorption is reduced by 24 % and compressive strength is increased by 101.6 %. The physical and mechanical properties of fired bricks incorporating 30 wt% of pelleting sludge are similar with bricks incorporating 20 wt% dyeing sludge without pelleting. The reduction in water absorption and porosity compared to that incorporating sludge without pelleting was mainly due to the reduction in the number and volume of pores of the same size. However, the introduction of more than 30 wt% dyeing sludge pellets is not conducive to improving the performance of the product, because a large number of macropores with size larger than 100 μm will be generated, which destroys the uniform and dense structure of the product. To ensure product quality meet the standard, the maximum dosage of dyeing sludge with pelleting is controlled below 30 wt%. This study provides an advanced method to improve the treatment efficiency of solid waste and the quality of products.

Investigating the Properties of Foamed Fly Ash and Metakaolin-based Geopolymer Concrete

A study has been carried out to produce environmentally friendly lightweight concrete by total replacement of cement with fly ash and metakaolin as binder material by adopting the pre-formed foam method. In this research, a geopolymer paste was produced by mixing fly ash or metakaolin with an alkali solution of sodium silicate and sodium hydroxide. Five mixes were produced at a density of 1000 kg/m³ as four foamed geopolymer concrete and one conventional foamed concrete made with cement paste as a binding medium. During the laboratory work, many trials were carried out to solve the segregation of the cellular structure from the mortar. From the results, it was noticed that the pore merging is more evident in foamed concrete mixes rather than in foamed geopolymer concrete mixes. In addition, the pore structure of fly ash-based geopolymer concrete is finer than that of metakaolin-based concrete geopolymer. The greater degree of pore merging resulted in forming of larger irregular voids and wider distribution of pore sizes and finally reducing strength. In general, the permeation, mechanical and thermal properties of foamed mixes made with geopolymer pastes are better than those of foamed mix made with cement paste. For a geopolymer paste, using metakaolin and fly ash C in combination helped in achieving the best properties i.e. reduction in water absorption by 34%, increasing strength by 78% and decreasing thermal conductivity by 44%.

Application of infrared spectroscopy methods in studying compositions for paper sizing

The paper proposes a method of infrared spectroscopy for objective control of the adhesive composition in the production of paper. For sizing paper, in order to increase mechanical strength and reduce water absorption, water-repellent materials are used. One of the most effective and used water-repellent material is ordinary pine resin rosin which is in short supply for the Republic of Uzbekistan. The paper investigates the properties of a new adhesive based on rosin from cherry resin for use in mass sizing in order to expand the range of sizing agents and reduce the share of imported components in the structure of local paper production. Infrared spectroscopy was used to identify the rosin-based glue from the resin of the cherry tree. The built-in device with a diamond crystal of the universal and compact Thermo Scientific Nicolet iS50 IR Fourier spectrometer made it possible to register spectra in the mid and far IR ranges up to 100 cm–1. The efficiency of sizing paper samples was studied by standard methods and evaluated by the following properties: density, tensile strength at stretching on a tensile machine, surface absorbency with one-sided wetting. Infrared spectra revealed the identity of the sizing agent from the resin of the cherry tree to the glue from the pine resin, taken for comparison, because their chemical composition is the same. A comparative analysis of the mechanical and surface properties of paper samples confirmed the possibility of using the studied sizing agent, since the obtained values are close to each other, while it is advisable to add in the range from 1 to 1.5 g per 100 g of dry cellulose raw materials. The use of infrared spectroscopy for express analysis of the composition of the sizing agent is promising, since it becomes possible to control the technological process and create glued types of paper products with desired properties that ensure print quality without loss of fine image details.

Organic silicone-modified waterborne epoxy coatings using aqueous curing agents technology

PurposeThe silicone modifications of two-component epoxy resin coatings are commonly built on epoxy resins rather than on epoxy curing agents. The silicone-modified epoxy curing agent system is rarely reported yet. This study aims to prepare the polysiloxane (PS)-modified waterborne epoxy coatings based on aqueous curing agents technology.Design/methodology/approachWaterborne epoxy curing agents with different contents of terminal epoxy PS were synthesized by reacting with triethylenetetramine, followed by incorporating of epoxy resin (NPEL-128) and polyethylene glycol diglycidyl ether. The waterborne epoxy coatings were prepared with the above curing agents, and their performance was investigated through thermogravimetric analysis, scanning electron microscopy, mechanical characterization, gloss measurement, chemical resistance test and ultraviolet (UV) aging experiment.FindingsThe results showed that the epoxy coating prepared by silicon-modified curing agent has higher gloss, better chemical resistance and UV resistance than the coating from unmodified curing agent with terminal epoxy PS and commercially available waterborne epoxy curing agent (Aradur 3986), as well as the competitive mechanical properties and heat resistance. Reduced water absorption on fibrous paper was also obtained with the help of silicon-modified curing agent.Originality/valueThese findings will be valuable for resin researchers in addressing the modification issues about waterborne epoxy resin and curing agent.

The impact of natural fibers’ characteristics on mechanical properties of the cement composites

The paper reviews the properties of cement composites reinforced with short fibres. The effect of natural fibres was investigated: cotton, sisal, jute, ramie, bamboo, and synthetic fibres: polymer and polypropylene. It was noticed that the fibres change the consistency of the mixture up to 15%. In the composite flexural strength tests, a change in strength by +/− 8% was observed, depending on the type of fibres used. The research shows that the use of natural fibres had a positive effect on the compressive strength by 27%, while the use of synthetic fibres caused its decrease by 4%. Additionally, it was noticed that the chemical composition, the diameter and the total length of the fibres in the element have an impact on the composite shrinkage. The fibre-containing composites showed an 8% higher water absorption compared to the non-fibre samples. The exception is the ramie fibres, which reduce water absorption. In general, a positive effect of natural fibers on the properties of cement composites has been noticed, however, in case of natural fibres application, a thorough further properties investigation is recommended.

E-glass/kenaf fibre reinforced thermoset composites fiiled with MCC and immersion in a different fluid

It is important to examine the long-term durability of glass-kenaf fibre reinforced phenolic resin composites when they are exposed to humid environments or submerged in water. Furthermore, the durability of such composites when immersed in different pH solutions have yet to be examined. As such, this present study examined the use of 4%, 8%, and 12% volume fractions (vfs) of microcrystalline cellulose (MCC) as a filler and reinforcement to improve the properties of glass fibre-kenaf reinforced phenolic resin composites. The flexural strength of these composites was examined both pre- and post-immersion in distilled water (pH 7), seawater (pH 8), and an acidic solution (pH 3) for 60 days. The diffusion mechanism, difussion coefficient, and water absorption concentration were also examined. The difussion coefficient and water absorption concentration occurred post-immersion in distilled water (pH7) and seawater (pH8) while the acidic solution (pH3) resulted in the highest loss of mass and size. Scanning electron microscopy (SEM) of the surfaces of the saturated composites indicated that fibre-matrix interfacial bonding was weak. However, composites that contained a higher vf of MCC exhibited stronger interfacial bonding between the matrix and constituents, thereby, reducing water absorption and diffusion. The flexural strength of the composite pre- and post-immersion was MCC12 > MCC8 > MCC4 > MCC0, in descending order of strength.

Quality Assessment of Waste from Olive Oil Production and Design of Biodegradable Packaging.

The use of olive pomace from olive oil production is still insufficient. The lingering olive pomace is harmful to the environment. On the other hand, the world is increasingly polluted with plastic or by-products from the production of biodegradable products. Considering these two problems, the aim of this work was to develop a mixture and create biodegradable disposable tableware characterized by high antioxidant activity. The disposable tableware was made by mixing olive pomace with teff flour or/and sorghum groats and lecithin. Baking was carried out at the temperature of 180 °C. The best variant of the mixture for the preparation of disposable tableware was olive pomace, teff flour, sorghum groats and lecithin. These vessels were the toughest, with low water absorption and had a high antioxidant potential due to the high content of polyphenols and omega acids. Protecting the cups and bowls with beeswax had a positive effect on reducing water absorption.

Mechanical and durability properties of modified High-Performance mortar by using cenospheres and Nano-Silica

The cement industries including excavating raw materials, burning processes, and transportation are responsible for 7% of worldwide carbon dioxide emissions due to rapid development in construction and urbanisation increased consumption of cement in the last few decades noticeably followed by environmental pollution. The incorporation of Supplementary Cementitious Materials (SCMs) like fly ash, silica fume, and granulated blast furnace slag in cement-based composites showed to be a remarkable technique to reduce cement consumption while enhancing its strength and durability. This study aimed to utilise Cenospheres (CS) and Nano-Silica (NS) to produce sustainable high-performance mortar based on the design of the experiment concept by incorporating (0–20) % of CS as a cement substitute and (0–2) % of NS as an additive admixture at a fixed W/B of 0.35. The performance of CS and NS in the mortar was evaluated based on mechanical properties (compressive and flexural strength), durability properties (water absorption, fire resistance, sulfuric acid attack, drying shrinkage), and microstructure. A denser and compacted structure was attained by the addition of (1–2) % of NS which improved the compressive and flexural strength of the mortar by (8–13) % and (23–26) % respectively, whereas employing 10 % of CS in the mortar reduced compressive strength as compared to the control mixture. However, CS particles increased the absorbance capacity of bending energy resulting in enhancing flexural strength by 15%. NS/CS mixtures showed excellent resistance to high temperatures and sulfuric acid by improving residual compressive strength. NS particles increased the drying shrinkage among all ages due to the high pozzolanic rate. In contrast, using 10% CS reduced the drying shrinkage by 10% as compared to the control mixture. The SEM analysis revealed that NS produced a denser and more compacted structure resulting in reduced water absorption capacity of the mortar as compared to CS mixtures. It was concluded that incorporating 10% of CS with 1% of NS in the mortar was the most adequate utilisation level to improve the stated above properties.