Water Impermeability Research Articles

Recent approaches of interface strengthening in fibre metal laminates: Processes, measurements, properties and numerical analysis

Recently, there is a pressing need for high-performance and lightweight structural materials in aircraft and automobile industry; fibre metal laminates (FMLs) are suggested ideal candidates for aviation industry. FMLs are hybrid composite material comprised of thin-metal sheets and fibre-reinforced polymers (FRPs). By combining the features of both components, FMLs possess high tolerance to fatigue damage, exceptional impact resistance and an outstanding weight-to-strength ratio. However, maintaining high structure integrity of FML layers – without debonding – remains the primary challenge in FMLs-based structures. The present review explores the recent developments in manufacturing techniques and surface treatments aimed at enhancing the interfacial strength between FML layers. Recently, adding nanofillers into FRPs and FMLs is gaining attention. These nanofillers can enhance mechanical performance of FRPs/FMLs, strengthen the interface in FMLs; and add functionalities such as gas and water impermeability. The article discusses the recent studies on employing nanofillers in FMLs and adhesively bonded structures; and their (nanofillers) role in enhancing the crack resistance of FMLs. It also explores failure mechanisms in FMLs through experimental methods and advanced numerical simulations. A comprehensive review of the existing studies assists in understanding the complex failure mechanisms, aiming to find optimal input conditions that yield desired mechanical performance. Furthermore, the article introduces machine learning techniques in adhesively bonded structures and potential application in FMLs-related research. The article concludes with perspectives on the limitations, current challenges, and future prospects for FMLs and nanofiller-reinforced FMLs.

Hermetic, Hybrid Multilayer, Sub‐5µm‐Thick Encapsulations Prepared with Vapor‐Phase Infiltration of Metal Oxides in Conformal Polymers for Flexible Bioelectronics

AbstractReliable long‐term function is crucial for flexible and soft bioelectronics. Mechanical defects and permeation of water molecules across the various device layers are the prime drivers of failure, and particularly in applications requiring continuous contact with biofluids (i.e. for implantable applications). To address demanding needs of miniaturization, mechanical compliance and water impermeability, ultra‐thin high‐barrier encapsulations are a promising way to improve device reliability. In this work, the encapsulation properties of vapour phase infiltration (VPI) of inorganic Al2O3 layers deposited by atomic layer deposition (ALD), as bilayers with TiO2, onto polyimide and parylene C organic substrates are investigated. The layers are grown in a single reactor and the infiltration is performed in a single process, with a resulting nanometric infiltration depth. Mechanical integrity and hermeticity are characterized through tensile fragmentation tests and accelerated aging tests. Flexible Magnesium sensors monitor water vapor permeability in situ. A remarkable improvement in the crack onset strain (∽2.56 times), interfacial shear strength (∽2.1 times), water vapour transmission rate (∽5.2 times) and lifetime performance (∽7.1 times) is achieved, compared to the non‐infiltrated ALD coatings. Pluri‐infiltrated multilayers are proposed as alternatives to conventional coatings. This work is envisioned to accelerate research progress on hermetic packaging of flexible bioelectronics.

Self-healing properties of mortar with crystalline admixture: experimental investigation and parameter optimization

The inclusion of crystalline admixture (CA) is a highly effective method for enhancing the self-healing properties of mortar. This study examined the complexing abilities of different complexing agents under varying temperatures, pH levels, and ion species in order to select effective complexing agents for diverse environments, as complexing agents play a crucial role in CAs. After determining the type of complexing agent, an orthogonal array design was used to optimize the components of CA, and the strengthening mechanism of CA for mortar was discussed through microstructure analysis. The results showed that the complexation behavior of triethanolamine (TEA) and glycine performed better than sodium citrate for different pH levels, temperatures, and ion species. Meanwhile, TEA and glycine showed complementarity at different stages, so TEA and glycine were used as complexing agents in this study. Based on the orthogonal experiment, the optimal contents of Na2SiO3, Na2CO3, TEA, glycine, Ca(COOH)2, and nano-SiO2 in CA were determined to be 1.0%, 1.0%, 0.04%, 1.0%, 0.5%, and 1.0%, respectively. Under the synergistic effect of TEA and glycine, the hydration of aluminate and ferrialuminate was accelerated, and the hydration degree of cement paste was increased. At 28 d, the contents of CaCO3, calcium-silicate-hydrate (C-S-H) gel, and ettringite of cement paste with CA were higher than these of plain paste, but its Ca(OH)2 content was lower. Although the Ca(OH)2 content in the cement paste with CA was lower, the Ca(OH)2 crystal structure filled in the pores was larger. Therefore, the mortar mixed with CA exhibited higher compressive strength, water impermeability, and self-healing ability.

Crafting Tunable Hollow Particles Using Antisolvent‐Driven Interlocking of Micron‐Sized Building Blocks

AbstractThe contribution of a hollow structure on the rheological behavior of granular suspensions remains un‐investigated due to the challenge of water impermeability. Here starch is used to fabricate water‐permeable hollow particles, as a model for granular suspensions and investigated the resulting microstructures and rheological behavior. The hollow structure is fabricated based on a bottom‐up method by assembling micron‐sized building blocks into a superstructure. A Pickering emulsion is heated to fuse the starch interface, then, upon antisolvent precipitation, the polymer strands interlock to form a rigid shell around the oil template. When the template is removed a hollow particle remained. These particles exhibited a specific volume >5‐times higher than unmodified starch and consequently a higher viscosity. Larger particles showed higher viscosity but are also more fragile. The template structure can be manipulated to fine‐tune their functionality. These micro‐sized building blocks made from edible materials can be used as the next generation of texturizers. Additionally, these water‐permeable colloidosomes present an innovative approach to understanding how micro‐architectures impact the rheological behavior of granular suspensions.

Bioresorbable Multilayer Organic-Inorganic Films for Bioelectronic Systems.

Bioresorbable electronic devices as temporary biomedical implants represent an emerging class of technology relevant to a range of patient conditions currently addressed with technologies that require surgical explantation after a desired period of use. Obtaining reliable performance and favorable degradation behavior demands materials that can serve as biofluid barriers in encapsulating structures that avoid premature degradation of active electronic components. Here, this work presents a materials design that addresses this need, with properties in water impermeability, mechanical flexibility, and processability that are superior to alternatives. The approach uses multilayer assemblies of alternating films of polyanhydride and silicon oxynitride formed by spin-coating and plasma-enhanced chemical vapor deposition , respectively. Experimental and theoretical studies investigate the effects of material composition and multilayer structure on water barrier performance, water distribution, and degradation behavior. Demonstrations with inductor-capacitor circuits, wireless power transfer systems, and wireless optoelectronic devices illustrate the performance of this materials system as a bioresorbable encapsulating structure.

Effect of colloidal nano silica on the freeze-thaw resistance and air void system of portland cement concrete

The present study investigates the impact of colloidal nano silica (CNS) on the freeze-thaw durability of concrete, with a particular focus on understanding the fundamental mechanism via a systematic analysis of the air void system. Experimental results suggest that the incorporation of CNS increases the total air content of the sample while reducing the average void size. This phenomenon can be attributed to the remarkable capacity of CNS to stabilize air bubbles within the concrete matrix, by a heightened viscosity and lower surface tension of the fresh concrete mixture. The increase in air void chambers facilitates the release of internal stress during freezing expansion, thereby enhancing the freeze-thaw resistance of the concrete. Additionally, the inclusion of CNS results in the formation of a denser cement matrix that improves the water impermeability of the concrete and prevents the ingress of water and other potentially corrosive substances.

Testing of tensile properties of two nonwoven geotextiles

The use of geosynthetics has become a common and unavoidable practice in geotechnical engineering, agriculture and environmental engineering. The main disadvantages of earthen construction materials are their insufficient tensile strength and inadequate water permeability or impermeability, depending on the problem to be solved. Such shortcomings are successfully solved by incorporating appropriate geosynthetics (geotextile, geogrid, geocells, geomembrane etc.) into earthen structures. The most used geosynthetic is geotextile, which can provide practically all functions expected from such a product. The aim of this paper was to present and analyse the relative results of multiple tensile tests performed on two nonwoven (NW) geotextiles to provide a realistic insight into the variability of their tensile properties. The obtained results showed a very similar variability of the tensile properties of the tested geotextiles.

Harnessing microbes for self-healing concrete – A review

This review explores the burgeoning field of microbially enhanced construction materials, with a special focus on self-healing concrete, through the lens of microbial biotechnology. Central to this discourse is the innovative use of bacteria, particularly Bacillus species, to address the pervasive issue of microcracks in concrete, a fundamental material in the construction industry. Traditional remedies, such as chemical admixtures and fiber reinforcements, offer partial solutions; however, self-healing concrete represents a paradigm shift, harnessing the natural calcite-precipitating ability of bacteria to autonomously repair cracks, thereby augmenting structural durability and longevity. Delving into the mechanics, the bacteria, embedded within the concrete matrix, remain dormant until crack formation triggers their metabolic pathways, leading to calcite production that effectively seals the fissures. This bio-mediated repair mechanism not only enhances the structural integrity of concrete but also aligns with sustainable construction practices by minimizing maintenance requirements and material wastage. The review extends beyond self-healing phenomena, encompassing broader applications of microbial technology in construction, including bio-concrete, bio-cement, and soil stabilization methods. These applications underscore the versatility of microbes in enhancing material properties such as compressive strength, tensile resilience, and water impermeability. Empirical evidence underscores the necessity of optimizing bacterial dosages and curing conditions to maximize the self-healing efficiency. Future research trajectories should aim to elucidate the complex interactions between microbial agents and concrete matrices, assess long-term performance, and evaluate the environmental and economic sustainability of microbial interventions in construction. The integration of microbial technology in construction materials heralds a new epoch of innovation, offering robust, sustainable, and resilient solutions to enduring challenges in the industry.

Evaluation of thermal and freeze-thaw resistances of the concretes with the silica fume addition at different water-cement ratio

The preparation of concrete with improved durability is an essential subject in the development of building and construction materials. This study presents the preparation and characterization of a high-strength concrete by activating ordinary 42.5 grade Portland cement (OPC) with silica fume (SF). The effect of the SF addition and water-cement (W/C) ratio on concrete durability including freeze-thaw, water permeability, mechanical and thermal resistance properties have been determined. When the water-cement ratio (W/C) in the SF added concrete is appropriately designed, for example, W/C 0.23, the compressive strength was 92.85 MPa, water absorption 0.7 %, 420 freeze-thaw cycles and water impermeability is W20. Residual strength of this concrete after thermal explosion at 600 °C for 2 h was 82 % of the original plain concrete, indicating that the obtained value is the true dense concrete. It also shows the concrete slump flow of 630 mm, which indicates its self-compacting behavior. The concrete prepared with W/C 0.29 achieved 365 freeze-thaw cycles, had 65.1 MPa compressive strength, W14 water impermeability, 1.8 % water absorption and 69 % residual strength after the thermal explosion at 600 °C. Concrete with washed aggregates has higher mechanical properties than concrete with unwashed aggregates. Freeze-thaw resistance has a direct relationship with the percentage of residual strength after explosion at 600 °C in all W/C ratios tested. Better durability and high resistance to temperature explosion was caused by the beneficial formation of the calcium silicate hydrate phase (C-S-H) in the silica fume added concrete.

Physicochemical analysis of primers and liquid membranes as asbestos’ encapsulant

Asbestos-containing materials pose significant health risks due to the potential dispersion of harmful fibers into the environment. This study presents a comprehensive physicochemical analysis of coatings, including primers and liquid membranes, designed to be applied on asbestos cement roofs, aiming to prevent the release of asbestos fibers and safeguard human health. Primers are normally used during the process of removing asbestos-containing panels to minimize the dispersion of fibers in the environment. By encapsulating the fibers on the surface, the primer helps to reduce the risk of fiber release during handling and removal. On the other hand, the primary goal of a liquid membrane is to encapsulate the asbestos fibers permanently, for long-term protection, preventing the potential health risks associated with asbestos exposure.To assess the reliability of primers and membranes is a matter of great importance especially for developing counties which have recently forbidden or are in the prohibition phase for the use of asbestos fibers. Two primers and two liquid membranes were investigated in a certified laboratory through a series of chemical and physical analysis. A primer was taken from commercial products in Colombia, a country that forbids asbestos but does not have legislation on these products, while two primers and a membrane were taken from a European country with high standards and decades of experience in the production of these materials to prevent asbestos exposure. The solid content, ash content, determination of primary solvents, thermogravimetry, infrared spectrum (FT-IR) of the polymer, infrared spectrum (FT-IR) of powders (fillers and pigments), and density were analyzed in the four products. Additionally, the membranes underwent testing for heat resistance, resistance to rain and freeze-thaw cycles, water impermeability, and accelerated aging (UVA 340, 1000 h). Furthermore, on membranes, adhesion capability (pull-off) was tested before and after heat-rain, freeze-thaw, UV ageing tests to ensure a durable bond between the coating and the asbestos surface.The results of the investigation revealed promising findings for both the primer and liquid membrane formulations. The primer demonstrated its potential applicability during the removal of asbestos panels, offering a preliminary safeguard against fiber dispersion. On the other hand, the liquid membranes exhibited excellent properties in encapsulating asbestos fibers effectively, providing long-term protection to the substrate. The Colombian membrane shown a calcium carbonate basis for the inorganic filler, with an almost pure acrylic polymer, while the second membrane shown a polymer styrene-acrylic matrix. This leads to less elasticity for the first membrane, and a possible exposure to acid rain attacks. Nevertheless, this chemical difference did not alter the results of the aging tests.

Sustainable Bio-Based Epoxy Resins with Tunable Thermal and Mechanic Properties and Superior Anti-Corrosion Performance.

Bio-based epoxy thermoset resins have been developed from epoxidized soybean oil (ESO) cured with tannic acid (TA). These two substances of vegetable origin have been gathering attention due to their accessibility, favorable economic conditions, and convenient chemical functionalization. TA's suitable high phenolic functionalization has been used to crosslink ESO by adjusting the -OH (from TA):epoxy (from ESO) molar ratio from 0.5:1 to 2.5:1. By means of Fourier-transform infrared spectroscopy, resulting in thermosets that evidenced optimal curing properties under moderate conditions (150-160 °C). The thermogravimetric analysis of the cured resins showed thermal stability up to 261 °C, with modulable mechanical and thermal properties determined by differential scanning calorimetry, dynamical mechanical thermal analysis, and tensile testing. Water contact angle measurements (83-87°) and water absorption tests (0.6-4.5 initial weight% intake) were performed to assess the suitability of the resins as waterproof coatings. Electrochemical impedance spectroscopy measurements were performed to characterize the anti-corrosive capability of these coatings on carbon steel substrates. Excellent barrier properties have been demonstrated due to the high electrical isolation and water impermeability of these oil-based coatings, without signs of deterioration over 6 months of immersion in a 3.5 wt.% NaCl solution. These results demonstrate the suitability of the developed materials as anti-corrosion coatings for specific applications.

Highly fluorinated non-aqueous solid-liquid hybrid interface realizes water impermeability for anti-calendar aging zinc metal batteries

The thermodynamic instability of zinc metal in aqueous electrolytes is attributed to severe interfacial problems at the zinc anode. In this study, we designed and synthesized a porous-fluorinated covalent organic framework (FCOF) to encapsulate liquid perfluoropolyether (PFPE) and Zn(OTf)2 using a host-guest strategy to effectively solve the static corrosion problem of the anode. The highly fluorinate solid-liquid interface restricted free water from contacting zinc, thus greatly improving the anti-calendar aging of aqueous zinc-metal batteries. The highly fluorinated solid-liquid hybrid was constructed as a water impermeability and defect-free protection layer on the Zn surface (denoted as P-PFL@Zn). The P-PFL@Zn had integrated advantages: the liquid PFPE filled structural voids to eliminate interfacial defects, improve contact with Zn, and effectively adapt to the dynamic interface fluctuations. The solid FCOF promoted fast ion transport, provided confined space, and exhibited strong adsorption with the liquid phase, restricting the mobility of PFPE and facilitating the tight adherence of FCOF to the Zn surface. Due to the synergistic effect between the FCOF and PFPE, P-PFL@Zn exhibited a 40-day anti-calendar aging cycle, high Zn2+ transference number, ultrafast charging, and dendrite-free features. The assembled high mass-loading (20 mg cm−2) MnO2 cathode-based full cells exhibited good practical level performance under intermittent cycle mode (1000-cycle life with 90% capacity retention) and continuous cycle mode (1000-cycle life with limited Zn usage and high current density).

Study on Durability Properties of Ternary Concrete Containing Agriculture Waste and Limestone

Abstract: This study focuses on exploring the potential of sugarcane bagasse ash (SBA) as a sustainable additive in concrete to enhance its durability properties for construction applications. The research investigated five different concrete mixes, including control, binary, and ternary cementitious systems. The binary mix incorporated 10% SBA, while the ternary system combined 10% SBA with varying proportions of limestone (10%, 15%, and 20%) as a partial substitute for Ordinary Portland cement (OPC). The durability properties of the concrete mixes, including acid resistance, sulphate resistance, sorptivity, water absorption, water impermeability, and porosity, were thoroughly evaluated. Based on the experimental results, the optimal mix proportion was identified as 10% SBA + 15% limestone, with the remaining 75% comprising OPC. The findings demonstrated that this specific combination of materials significantly improved the durability of the concrete, indicating the potential of SBA as an eco-friendly and effective solution for sustainable construction practices.

Mechanical properties, permeability and microstructure of steam-cured fly ash mortar mixed with phosphogypsum

Incorporating proper amount of fly ash (FA) contributes to improve the long-term performance of steam-cured mortar. However, with the introduction of stringent environmental policies, the reserves of high-quality FAs are decreasing and the costs are increasing. In this study, phosphogypsum is used to replace part of FA to produce high-quality prefabricated components, and mechanical properties, water permeability, microstructure and environmental benefits of samples are investigated. The research results show that replacing FA with proper amount of PG can greatly increase mechanical properties of steam-cured FA mortar and improve its water impermeability. When 10% of PG is applied to the steam-cured FA mortar, the 1-d and 28-d compressive strengths of the samples increase by 11% and 5.37%, respectively, relative to the control mortar. The results of microstructure characterization show that this is due to the generation of swelling products and the increase of the reaction degree of FA. When PG and steam curing are applied in combination, FA is severely corroded and a gel phase product is generated, which contributes to increase the strength of specimen. In addition, using appropriate amount of PG also brings obvious economic and environmental benefits for prefabricated components.

Impermeable Graphene Skin Increases the Heating Efficiency and Stability of an MXene Heating Element.

A Joule heater made of emerging 2D nanosheets, i.e., MXene, has the advantage of low-voltage operation with stable heat generation owing to its highly conductive and uniformly layered structure. However, the self-heated MXene sheets easily get oxidized in warm and moist environments, which limits their intrinsic heating efficiencies. Herein, an ultrathin graphene skin is introduced as a surface-regulative coating on MXene to enhance its oxidative stability and Joule heating efficiency. The skin layer is deposited on MXene using a scalable solution-phased layer-by-layer assembly process without deteriorating the excellent electrical conductivity of the MXene. The graphene skin comprises narrow and hydrophobic channels, which results in ≈70 times higher water impermeability of the hybrid film of graphene and MXene (GMX) than that of the pristine MXene. A complementary electrochemical analysis confirms that the graphene skin facilitates longer-lasting protection than conventional polymer coatings owing to its tortuous pathways. In addition, the sp2 planar carbon surface with a low heat loss coefficient improves the heating efficiency of the GMX, indicating that this strategy is promising for developing adaptive heating materials with a tractable voltage range and high Joule heating efficiency.

Experimental Study on the Performance of Steel-Fiber-Reinforced Concrete for Remote-Pumping Construction.

Remote-pumped concrete for infrastructure construction is a key innovation of the mechanized and intelligent construction technology. This has brought steel-fiber-reinforced concrete (SFRC) into undergoing various developments, from conventional flowability to high pumpability with low-carbon features. In this regard, an experimental study on the mixing proportion design and the pumpability and mechanical properties of SFRC was conducted for remote pumping. Using the absolute volume method based on the steel-fiber-aggregate skeleton packing test, the water dosage and the sand ratio were adjusted with an experimental study on reference concrete with the premise of varying the volume fraction of steel fiber from 0.4% to 1.2%. The test results of the pumpability of fresh SFRC indicated that the pressure bleeding rate and the static segregation rate were not the controlling indices due to the fact that they were far below the limits of the specifications, and the slump flowability fitted for remote-pumping construction was verified by a lab pumping test. Although the rheological properties of the SFRC charactered by the yield stress and the plastic viscosity increased with the volume fraction of steel fiber, those of mortar used as a lubricating layer during the pumping was almost constant. The cubic compressive strength of the SFRC had a tendency to increase with the volume fraction of steel fiber. The reinforcement effect of steel fiber on the splitting tensile strength of the SFRC was similar to the specifications, while its effect on the flexural strength was higher than the specifications due to the special feature of steel fibers distributed along the longitudinal direction of the beam specimens. The SFRC had excellent impact resistance with an increased volume fraction of steel fiber and presented acceptable water impermeability.

Nanomontmorillonite Reinforced Fibre Cements and Nanomontmorillonite-Nanosilica Reinforced Mortars

In this study the effect of an organomodified nanomontmorillonite (nMt) dispersion (nC2) and of a powder type nMt (nC4), were compared in quaternary low carbon footprint fibre-reinforced cementitious nanocomposites and mortars. 60% Portland cement, 20% limestone (LS) and 20% fly ash plus fibres/superplasticizer comprised the reference paste. nMt was added at 1% by mass. Pastes were investigated in terms of flexural strength, thermal properties, density and water impermeability. Neither of the two types offered strength enhancement. nC2 showed some potentials at late ages (90 days). Thermal gravimetric analyses showed limited additional pozzolanic activity towards the production of additional C–S– H at day 90, in agreement with flexural strength results and X-ray diffraction analysis, which showed the consumption of Ca(OH)2 even at day 28. No change in density was observed, whereas water impermeability tests showed that nC2 was more effectively organomodified not allowing water to be absorbed neither in the short nor in the long term, while nC4 at later ages seemed to be absorbing water back. Lastly, cubes of mortars were prepared and tested in compression in an attempt to fully investigate the potentials of the formulations. The effect of using simultaneously nMt and nanosilica (nS) was also recorded, however no increase in compressive strength was observed. The long-term density of the mortars was also investigated, results suggesting poor compaction which was not adjusted with the use of admixtures. These results are in support of previous studies undertaken in the field, showing that the purpose of use of organomodified nMt’s must be clearly defined before any formulations are designed.

Corrosion behavior of embedded pad hook in glass fiber reinforced concrete

AbstractGlass fiber reinforced concrete (GFRC) comprises of hydration products of cement or cement plus sand, and glass fibers which take part in the concrete as reinforcement characteristics. GFRC has been used for over 50 years in several construction elements, such as facade panels, decorative no recoverable formwork, and other products. However, various anchor elements and pad hooks are needed to attach large or small parts made of GFRC panels to the main structure of the buildings. The corrosion rate of embedded metal fasteners over time is related to the water impermeability properties of the GFRC elements. In this study, corrosion of an electro galvanized pad hook embedded in 10–20 mm of the GFRC panel was investigated as a result of the salt spray test performed in accordance with ASTM B 117 standards. At the end of the experiment, the embedded pad hook was taken from the GFRC and analyzed by scanning electron microscopy, energy‐dispersive spectroscopy methods. The results showed that the embedded pad hook in the GFRC, which was examined in the test procedures comply with the TS EN 12467 standards, was not corroded by 120‐h test carried out in accordance with ASTM B 117 standards.

Statistical Study of the Effectiveness of Surface Application of Graphene Oxide as a Coating for Concrete Protection

Improving the protection of concrete by applying graphene oxide (GO) as a surface treatment has become the objective of the present study. This study focuses on performing a statistical analysis to study different levels of GO application as an exterior coating, thus observing the effectiveness of the coating and the optimization of the treatment material for concrete protection. Four tests were performed to define concrete durability, such as pressurized water penetration, capillary absorption, freeze-thaw resistance and carbonation resistance. The results showed an increase in concrete durability with any level of GO application on the surface, considering that the optimum amount of application for water impermeability and freeze-thaw resistance is 26.2 µg/cm2, since it was possible to reduce pressurized water penetration by 45%, capillary water absorption by 57% and freeze-thaw detachment by 25%. However, the optimum application rate for carbonation resistance is 52.4 µg/cm2, reducing carbonation by almost 60%. In conclusion, if the concrete is going to be exposed to less aggressive environments, the application of a mild surface coating of GO is sufficient for its protection, and if the concrete is going to be exposed to more aggressive environments, it is necessary to increase the amount of GO. The performance of GO as a coating significantly increased the degree of protection of the concrete, increasing its service life and proving to be a promising treatment for concrete surface protection.

РАЗРАБОТКА КОМПЛЕКСНОЙ ДОБАВКИ ДЛЯ ПРОИЗВОДСТВА БУРОНАБИВНЫХ СВАЙ

The article presents the results of the effect of the additive on water resistance, frost resistance and workability, which are one of the main indicators of the physical and mechanical properties of concrete. In the presented work the authors used a complex additive containing alkali (caustic soda), post-alcohol bard and hardening regulator (gypsum) in different % ratios. It is shown that the use of a complex additive in the composition of concrete significantly increases the water resistance and frost resistance compared with the control samples. The influence of the complex additive on the workability of concrete mixture has been studied. It has been established that the complex additive allows obtaining highly workable concrete mixtures and reducing their water separation, providing high preservation of concrete mixtures. The water impermeability of concrete is also significantly improved - the water impermeability grade increases by 4 steps in comparison with the concrete without additive. The proposed method speeds up the process of determining the concrete water impermeability grade and allows you to determine the water resistance grade and the degree of permeability of concrete on the basis of the obtained dependencies. When adding a complex additive in an amount of up to 7 % of the weight of cement increases the brand on frost resistance. It is found that the concrete with the studied complex additive has high physical and mechanical properties. The optimum dosages of the considered additive were found and used in the present work.