Nanosilica Content Research Articles

Thermal properties of nano-silica added concrete

As energy costs are rising, the utilization of thermal insulating materials during construction has assumed paramount significance. The response of different building components to changes in external temperature depends on the material’s thermal properties. The investigation connected to concrete material thermal properties is an essential factor when concrete is used for constructing green buildings. The effect of adding nano-silica on the concrete’s thermal properties is explored, and the findings are shown in this paper. The experimental results reveal that compressive strength increases and density reduce for nano-silica added concrete. The investigation indicates that thermal conductivity and thermal diffusivity decrease for concrete, whereas specific heat increases with a rise in nano-silica content. Also, a mathematical model was developed for the calculation of thermal conductivity.

Efficacy of Nanosilica Coatings in Calcium Looping Reactors.

Nanosilica coatings are considered a simple physical treatment to alleviate the effect of cohesion on powder flowability. In limestone powders, these coatings buffer the rise in cohesion at high temperatures. Here, we investigate the role of particle size in the efficiency (and resilience) of these layers. To this end, this work examines a series of four limestone powders with very sharp particle size distributions: average particle size ranged from 15 to 60 μm. All the samples were treated with nanosilica at different concentrations from 0 to 0.82 wt %. Powders were subjected to short- and long-term storage conditions in calcium looping based systems: temperatures that vary from 25 to 500 °C and moderate consolidations (up to 2 kPa). Experiments monitored powder cohesion and its ability to flow by tracking the tensile strength of different samples while fluidized freely. Fluidization profiles were also used to infer variation in packings and the internal friction of the powder bed. Interestingly, for particle sizes below 50 μm, the nanosilica treatment mitigated cohesion significantly-the more nanosilica content, the better the flowability performance. However, at high temperatures, the efficiency of nanosilica coatings declined in 60 μm samples. Scanning electron microscopy images confirmed that only 60 μm samples presented surfaces barely coated after the experiments. In conclusion, nanosilica coatings on limestone are not stable beyond the 50 μm threshold. This is a critical finding for thermochemical systems based on the calcium looping process, since larger particles can still exhibit a significant degree of cohesion at high temperatures.

Synergetic effects of hybrid nano-blended cement on mechanical properties of conventional concrete: Experimental and analytical evaluation

The present experimental and analytical study aims to modify conventional cement to create a higher strength-to-weight ratio concrete using hybrid nanomaterials, i.e., Carbon Nanotubes (CNTs) and Nano-Silica (NS), as a partial replacement for cement (Nano-blended cement). In this study, three CNTs and four NS contents were chosen to evaluate the mechanical properties of concrete. 234 tests for specimens at 7, 28, and 90 days were carried out to achieve the optimum composition of the nanoparticles for the compressive strength and splitting tensile strength. Test results of the specimens examined at 28 days illustrate that the compressive strength and tensile strength were improved by 125 % by the inclusion of 0.1 % CNT + 1.5 % NS and by 110 % by using 0.5 % CNT + 1.0 % NS, respectively. Moreover, the strength-enhancement mechanism of novel concrete was visualized by scanning electron microscopy (SEM). Since conventional high-performance concretes, due to the high amount of cement required, are not environmentally friendly, the novel Nano-blended cement can create high-performance concretes without adding more cement or any concrete ingredients. In addition, using Nano-blended concrete results in a lighter structure with smaller members' size and a more lightweight foundation, and therefore is more cost-effective and sustainable than conventional concrete.

Effect of nano-silica on structure and properties of high sulfate resistant Portland cement mixed with mineral powder or fly ash

Hydrating-hardening properties of high sulfate resistance Portland cement (HSRPC) mixed with 35 wt% mineral powder (MP) or fly ash (FA) and the action mechanism of nano-silica (NS) under the condition of low-calcium hydrating phase were studied in this paper. Rheology, fluidity, setting time and compressive strength were investigated to explore the effect of NS on the basic physical properties of HSRPC doped with MP or FA. Mercury intrusion porosimetry (MIP), ultrasonic crack analysis, hydration heat and thermogravimetry (TG) were investigated to analyze the hardened structure and the hydration mechanism. The conclusions were as follows: For HSRPC with MP, the 0.1–0.5 wt% NS increased the yield stress, decreased the fluidity and prolonged the setting time. However, when NS content increased from 0.1 wt% to 0.5 wt%, the cumulative porosity increased by 9.8% and the 60 h (60 h) cumulative hydration heat decreased by 14.6% because NS with high specific surface area inhibited the hydration of HSRPC, but its particle filling increased the porosity of harmless pores to improve the 3day (3d) compressive strength slightly. After 28d of hydration, the compressive strength increased by 2.8%, ultrasonic amplitude increased by 19.3%, and calcium hydroxide (CH) decreased by 6.6%, indicating that NS fully reacted with CH generated by HSRPC hydration. For HSRPC with FA, the 0.1–0.3 wt% NS increased the yield stress, setting time and 3d compressive strength and decreased the cumulative porosity. The 60 h cumulative hydration heat increased from 155.9 J/g to 198.5 J/g. The ultrasonic amplitude of 28d hardened paste increased from 10.91 V to 17.01 V and the CH content decreased from 15.29% to 14.1%. It indicated that the 0.1–0.3 wt% NS with high activity reacted with CH and further promote cement hydration to generate a large number of hydration products to improve the densification and performance, especially at the early age.

A one step self-cleaning surface with robust superhydrophobic and photocatalytic properties: Electrostatic sprayed fluorinated ethylene propylene mixed with nano TiO2–SiO2 particles

In this research, a one-step and environmentally friendly method, free from the complexity of chemical techniques, was utilized to prepare a superhydrophobic surface that can be implemented on large scale. To this end, at first, silica nanoparticles were made hydrophobic through the silanization method, then got mixed with titanium dioxide nanoparticles and fluorinated ethylene propylene (FEP). Afterward, the combined materials were deposited on aluminum substrate using an electrostatic spraying method. In order to assess the fabricated surface, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and contact angle measurement are accomplished. In addition, the photocatalytic activity by the degradation of oleic acid and methylene blue (MB) upon UV exposure was studied. Results indicated formation of a superhydrophobic photocatalyst with contact angle over 150 ° . This superhydrophobic surface containing nano silica content 12 wt.% and TiO 2 20 wt.% exhibited excellent photocatalytic activities in the organic materials degradation. The obtained photocatalyst surfaces also revealed proper stability in acidic (pH = 5) and alkaline (pH = 11) media. Moreover, a suitable stability was observed in the fouling medium with duration 10 h while no change in the static contact angle occurred.

Flexural Behavior of High Strength RC Beams Incorporating Nano-Silica and Macro-Polypropylene Fiber

This paper investigates the flexural behavior of high-strength RC beams experimentally to assess the effect of Nano-silica (NS) and Macro-Synthetic High Strength Polypropylene Fiber (MPF). Ordinary Portland cement was partially replaced by the NS and MPF with different proportions to produce four concrete mixtures. Tests were conducted on the full-scale high-strength RC beams, including first crack load, failure load, deflection, concrete strain, steel strain, and mode failure, which were examined and compared. In addition, the tests on the mechanical properties of high-strength concrete mixtures were also conducted at the ages of 28 and 56 days. The test results concluded that the addition of NS and MPF significantly improved the first-cracking and failure loads and decreased deflection at levels of cracking and failure loads. Additionally, an increase in NS content resulted in a minor increase in the ultimate strain related to the failure loads. Furthermore, the mix of 3% NS with 0.5% MPF was found to lead to the highest mechanical characteristics of concrete. The improvements were the concrete compressive strength by 33.6%, split tensile strength by up to 54.1%, and flexural strength by up to 28.3% compared with control specimens.

Improvement of physical and thermal properties of polyvinyl butyral coating with nanosilica

In this paper, polyvinyl butyral (PVB) coatings with different nanosilica contents (0- 1.5 weight percent (wt%) were prepared for improving properties such as mechanical properties, corrosion protection, thermal oxidation stability of coating. Presence of nanosilica in coating was characterized by FT-IR. Corrosion resistance of PVB coatings containing nanosilica was investigated by salt mist testing. Effects of nanosilica on adhesion, flexural strength and relative hardness and thermal oxidation stability of PVB coatings were also examined. Nanosilica with content of 1.2 wt% significantly improved mechanical properties, corrosion resistance and thermal oxidation stability of PVB coatings.

Experimental and Theoretical Study on Carbonization Coefficient Model of NS/SAP Concrete

Carbonization coefficient research has great significance in concrete carbonization evaluation. Nano-silica (NS) can reduce the content of Ca(OH)2, which is generated during the hydration of concrete, resulting in improved carbonization resistance and compressive strength of concrete. This paper investigates the carbonization effects of concrete with internal curing, such as Super Absorbent Polymer (SAP). The research shows that SAP can promote hydration of the internal concrete but form tiny pores after releasing the water completely, which may cause a reduction of carbonation resistance of concrete. The concrete was modified by adding SAP, ranging from 0 to 0.24%, to ascertain the optimal content of SAP. The addition of NS changed the concrete from 0 to 1.5% to confirm the optimal range of NS. To establish a reasonable suitable theoretical model of NS/SAP concrete, the influence factors of the carbonization coefficient of concrete were analyzed first. Later, the accelerated carbonization test was carried out on 100 mm × 100 mm × 100 mm cube specimens with different carbonization time to obtain the compressive strength and carbonization depth to establish the carbonization coefficient model of NS/SAP concrete. Before analyzing experimental data, the specimens were randomly divided into fitting and validation groups. Based on the regression analysis of the fitting group, the carbonization coefficient model was established, which embodied the influence of various parameters on concrete carbonization, including SAP content, NS content, water–cement ratio, CO2 concentration, temperature, relative humidity, and compressive strength. According to the validation analysis of the verification group, the mean relative error of the model is 5.04%, and the residual mean square error is 0.1751. Compared with the literature models, this study’s carbonization model can accurately predict the carbonization depth of NS/SAP concrete.

Analysis and prediction of the effect of Nanosilica on the compressive strength of concrete with different mix proportions and specimen sizes using various numerical approaches

AbstractIntroducing nanotechnology in concrete is one of the most significant successes in enhancing the mechanical properties of concrete. It affects the quality of the microstructure of the concrete due to its extremely small nanoparticles leading to a faster reaction due to its large surface area. The nanoparticles fill the concrete's pores, resulting in considerably improved strengths in the early ages of the concrete. This research used six models; linear regression (LR), multilinear regression (MLR), nonlinear regression (NLR), pure quadratic (PQ), interaction (IA), and full quadratic (FQ), to predict the compressive strength of the concrete modified with different Nanosilica contents for various mix proportions. The models were applied to three datasets, with 420 collected from several research studies. The ranges of the concrete mix proportions used in this study were as follows, water/cement ratio (w/c) ranged between 0.1 and 1, cement content (C) ranged between 153.81 and 1200 kg/m3, fine aggregate content (FA) ranged between 492 and 2270 kg/m3, coarse aggregate content (CA) ranged between 617 and 2900 kg/m3, superplasticizer (SP) ranged between 0% and 6.7%, coarse aggregate size (CAS) ranged between 6 and 50.8 mm, fine aggregate size (FAS) ranged between 0.025 and 10 mm, Nanosilica content (NS%) ranged between 0% and 15%, w/c of 0.4–0.6 and the curing time (days) ranged between 3 and 180. The compressive strength of the collected datasets ranged from 3 to 120 MPa. The parameters that have improved the analyzed datasets of the compressive strength were the content of Nanosilica and the SP. The models were assessed for their accuracy using multiple assessment criteria; the most evident ones are; the objective function (OBJ), root mean square error (RMSE), Scatter Index (SI), and the maximum absolute error (MAE). The analytical models and the model comparison operations will be shown in detail in this research, indicating that the most effective and accurate model is the FQ model; where coefficient of determination (R2) of 0.96, RMSE of 3.49 MPa, MAE of 2.96 MPa, and SI of 0.08 were conducted from the analytical studies. From the developed models, the compressive strength of the concrete up to a high compressive strength level with high accurately can be predicted. Also, the compressive strength of the concrete can be accurately predicted for various sizes of aggregate and specimens.

Rutting Performance of Nano-Silica-Modified C320 Bitumen

Nanomaterials exhibit novel properties and profound attributes as an additive in asphalt binder modification. However, the application of nano-silica in asphalt binders and mixture modification is still limited, and further research is required. Along these lines, in this work, nano-silica with a content from 2% to 8% and an increment of 2% was utilized in modifying the bitumen binder type C320, which is considered the most conventional type of bitumen used in Western Australia road asphalt mixtures. Various tests were performed to assess their properties, including complex shear modulus, penetration, softening point, and multiple stress creep recovery (MSCR) test. The extracted results revealed an increase in the strength and stiffness properties by lowering the penetration, improving the softening point, and increasing the complex shear modulus of all the nano-silica-modified bitumen samples. Interestingly, much of the content of nano-silica leads to higher rutting resistance. However, the rutting resistance was affected by the size of the nano-silica coated with the silane coupling agent. The ideal sample of nano-silica-modified C320 was determined as NS-15 nm (NS-A), which can improve the rutting resistance by about 7.1 kPa. In the current study, the results of the penetration and softening point using 6–8% of NS-A resulted in a relatively significant improvement of up to 45% in comparison with the non-modified binders. Nevertheless, the rutting resistance of the modified asphalt mixtures needs to be further investigated in the future to elaborate on the impact of nano-silica as modified binders on the mechanical properties of Australian asphalt mixtures.

Role of polyaniline coating on nanosilica particles in polyvinylidene fluoride nanocomposites for energy storage

Polymer nanocomposites, which are characterized by a high dielectric permittivity, are intensively studied for microelectronic devices and energy storage applications. Poly(vinylidene fluoride) (PVDF) has a higher dielectric permittivity among polymers, is flexible, lightweight and easy to be processed. One route to enhance its mechanical and dielectric properties is the addition of inorganic nanofillers. Therefore, PVDF was melt compounded with nanosilica in various proportions, from 5 to 30 wt%. For enhancing the stored and released electric energy densities, polyaniline (PANI) was obtained in situ on the surface of nanosilica in both acid and basic media; further the nanosilica particles coated with PANI were incorporated in PVDF by melt compounding to improve the dielectric properties by adding new interfaces. The addition of nanosilica in PVDF led to a strong increase in its storage modulus without reducing its good thermal stability. Moreover, an important increase in PVDF permittivity was determined by increasing content of nanosilica in nanocomposites. PANI coating influenced both thermal and mechanical properties and led to nanocomposites with more stable dielectric permittivity and lower dielectric loss than neat PVDF at frequencies between tens Hz and tens kHz, which is very important for energy storage applications.

Efficient Physical Mixing of Small Amounts of Nanosilica Dispersion and Waterborne Polyurethane by Using Mild Stirring Conditions

Good dispersion of nanosilica particles in waterborne polyurethane was obtained by mild mechanical stirring when 0.1-0.5 wt.% nanosilica in aqueous dispersion was added. The addition of small amounts of nanosilica produced more negative Z-potential values, increased the surface tension and decreased the Brookfield viscosity, as well as the extent of shear thinning of the waterborne polyurethane. Depending on the amount of nanosilica, the particle-size distributions of the waterborne polyurethanes changed differently and the addition of only 0.1 wt.% nanosilica noticeably increased the percentage of the particles of 298 nm in diameter. The DSC curves showed two melting peaks at 46 °C and 52 °C, as well as an increase in the melting enthalpy. In addition, when nanosilica was added, the crystallization peak of the waterborne polyurethane was displaced to a higher temperature and showed higher enthalpy. Furthermore, the addition of 0.1-0.5 wt.% nanosilica displaced the temperature of decomposition of the soft domains to higher temperatures due to the intercalation of the particles among the soft segments; this led to a change in the degree of phase separation of the waterborne polyurethanes. As a consequence, improved thermal stability and viscoelastic and mechanical properties of the waterborne polyurethanes were obtained. However, the addition of small amounts of nanosilica was detrimental for the wettability and adhesion of the waterborne polyurethanes due to the existence of acrylic moieties on the nanosilica particles, which seemed to migrate to the interface once the polyurethane was cross-linked. In fact, the final T-peel strength values of the joints made with the waterborne polyurethanes containing nanosilica were significantly lower than the one obtained with the waterborne polyurethane without nanosilica; the higher the nanosilica content, the lower the final adhesion. The better the nanosilica dispersion in the waterborne polyurethane+nanosilica, the higher the final T-peel strength value.

Preparation and evaluation of a fluorinated nano-silica superhydrophobic coating for cement pavement

To reduce the traffic risk of pavement icing, a fluorinated nano-silica superhydrophobic coating for cement pavement was prepared with fluorinated nano-silica, carbon black, and waterborne epoxy resin. The component and spraying dosage were analyzed for optimal performance by combining the fluorination verification, component contents determination, and spraying dosage optimization. The engineering performance was evaluated for applicability, basing anti-icing performance and pavement durability. The test results showed that the fluorine group has successfully drafted on the nano-silica. The determined content of nano-silica is 75 wt% and of carbon black is 17.5 wt% of waterborne epoxy resin. The optimal application amount is 0.5 L/m2 to balance the requirement of superhydrophobic property and skid resistance. Meanwhile, the prepared coating has a good engineering performance. It can boost 70 % ability to repulse incoming water droplets, delay 40 % time of ice formation, and increase 40 % ratio of ice-layer removal compared with the uncoated. It can also maintain the basic appearance and superhydrophobic property after about 150,000 times wheel abrasion or three high-low temperature cycles. This demonstrates that the prepared coating has a good potential for practical use.

Mechanical properties of unbound granular materials reinforced with nanosilica

The development of new technologies for soil improvement has been a hot research topic in the fields of geological engineering, geotechnical engineering, and road engineering. Nanomaterials have been proven to offer significant advantages in the field of geotechnical material enhancement due to their unique structures and excellent properties. The effect of nanosilica amount on the stress-strain behavior, elastic modulus, shear strength, and shear parameters of unbound granular materials was investigated, and its potential enhancement mechanism was discussed in this research. Treated samples with nanosilica contents (by weight) of 0,1%, 2%, 3%, 3.5%, 4%, and 4.5% were prepared and rigorously examined through unconsolidated undrained (UU) triaxial tests under different confining pressures. Also, the intrinsic mechanism and variations in the microstructure of the specimens were investigated by the computed tomography (CT) and scanning electronic microscope (SEM). Testing results showed that with the addition of more nanosilica, the elastic modulus and shear strength of the specimens increased and the ductility decreased. The apparent cohesion of the treated specimens increased approximately linearly and had almost as little effect on the internal friction angle. The maximum improvement rate was obtained at 3.5% of nanosilica content. The CT and SEM scanning results indicated that the control specimen has a higher void ratio than the treated specimens, and the filling and nucleation effects of nanomaterials may be the intrinsic mechanism to improve the mechanical properties of unbound particulate materials. The experimental results contribute to enriching the application of nanomaterials in geotechnical engineering, guiding the optimization of mechanical properties of unbound granular materials.

High content of spherical nanosilica filled epoxy resin master batch with low viscosity and superior thermomechanical performance

Spherical nanosilica is reckoned as an indispensable filler in electronic encapsulation to improve the thermomechanical performance of epoxy resin matrix. How to achieve higher content and better dispersion of spherical nanosilica in epoxy resin remains a big challenge. Here, Surface-modified spherical nanosilica was prepared on the basis of Stöber method in the presence of binary silane coupling agents as surface modifier. High content of as-modified spherical nanosilica was introduced into bisphenol F epoxy resin (denoted as EP) matrix by one-step liquid-phase method to afford SiO2/EP master batch. The viscosity, thermal stability and dynamic thermo-mechanical properties of SiO2/EP composites with different filler contents derived from SiO2/EP master batch were systematically investigated. Findings indicate that organosilanes grafted onto the surface of silica nanoparticles contribute to improving their compatibility and dispersibility within EP matrix, leading to a relatively low level of viscosity of EP-matrix composites especially under a high nanofiller dosage and improving their dynamic thermomechanical properties and thermal expansion stability as well. Moreover, SiO2/EP master batch made from liquid-phase method exhibits better performance compared with that prepared by physical blending way. It is a facile way to prepare EP master batch with high filler content, low viscosity and superior performance, meanwhile brings processing convenience for application in electronic encapsulation.

Rheological properties and early mechanical strength of oil-well cement modified by hybrid nano-silica and nano-hexagonal boron nitride

The purpose of this study was to investigate the effect of the content of hybrid nano-silica (NS) and nano-hexagonal boron nitride (h-BN) on the rheological properties and early mechanical strength of oil-well cement using response surface methodology (RSM). Based on the microstructures revealed by X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy, the modification mechanism of cement mixed with a hybrid of NS and h-BN in the early stage of hydration was studied. It was found that the rheological properties of fresh oil-well cement slurries with added NS and h-BN conformed to those of Bingham fluids. An increase in NS content worsened the fluidity of the cement, whereas the h-BN content did not affect its fluidity. The early compressive, flexural, and splitting tensile strengths at the end of the 3-day curing time increased by 12.33 MPa/47.24 %, 1.88 MPa/29.01 % and 1.24 MPa/53.22 %, respectively. The pozzolanic reaction of NS begins to occur in the early stages of cement hydration. The synergistic effect of the added NS and h-BN increased the density of the early hydration product of the cement. The h-BN mainly enabled the bridging, filling, and crack-resistant effects in the early oil-well cement.

Hydration and Mechanical Properties of High-Volume Fly Ash Concrete with Nano-Silica and Silica Fume.

This study investigated the effects of nano-silica (NS) and silica fume (SF) on the hydration reaction of high-volume fly ash cement (HVFC) composites. In order to solve the dispersibility problem caused by the agglomeration of NS powder, NS and NSF solutions were prepared. NS content and SF content were used as main variables, and an HVFC paste was prepared in which 50% of the cement volume was replaced by fly ash (FA). The initial heat of hydration was measured using isothermal calorimetry to analyze the effects of NS and SF on the initial hydration properties of the HVFC. In addition, the compressive strength was analyzed by age. The refinement of the pore structure by the nanomaterial was analyzed using mercury intrusion porosimetry (MIP). The results show that the addition of NS and SF shortened the setting time and induction period by accelerating the initial hydration reaction of HVFC composites and improved the compressive strength during the initial stage of hydration. In addition, the micropore structure was improved by the pozzolanic reaction of NS and SF, thereby increasing the compressive strength during the middle stage of hydration.

Durability of Nano-Reinforced Recycled Aggregate Concrete under Load and Chloride Ingress.

The improved performance of recycled aggregate has an important impact on its use in engineering. In this study, to improve the weak surface properties, recycled aggregates were treated by nano-silica slurry and applied to concrete beam specimens. Under the action of cracks caused by continuous load and drying-wetting cycles with chloride ingress, the effects of different recycled aggregate additions, nano-silica contents and crack widths on the self-healing performance of cracks and the resistance to chloride ingress of the recycled concrete beams were investigated. It was found that the self-healing rate of cracks increased first and then decreased with increased nano-silica content, reaching a maximum when the content reached 0.4%. Greater amounts of additive in the recycled aggregate increased the concentration of free chloride ions in cracks. However, this concentration was found to be weakened in nano-reinforced aggregate. From a comprehensive perspective, the relative chloride ion concentration can be effectively reduced by controlling the crack width to be smaller than 0.12 mm and using improved recycled aggregates treated with 0.2% nano-silica material. This study provides a reference for the application of recycled aggregate concrete under severe environmental and load conditions.

Experimental Analysis of Mechanical and Thermal Characteristics of Luffa/Epoxy Polymer Composite under the Influence of Nanosilica

In the current work, the experimentations have been accomplished to assess the impact of diffusing nanosilica particles in epoxy matrix on the mechanical and thermal performance of the luffa fibre reinforced epoxy composite material. The matrix and fibre composition are fixed as 80 : 20 throughout the study, and the nanosilica is disbanded in diversified volume fractions of 0%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%, respectively, while preparing luffa/epoxy/nanosilica (LES) composite samples. The mechanical characteristics, such as tensile, flexural, and impact behaviour of the composite, and the thermal properties, namely, thermal stability and thermal conductivity, are examined for the LES samples. The experiments are accomplished as per the ASTM standards. The results revealed that the assimilation of nanosilica particles in epoxy has improved the mechanical and thermal characteristics of the composite significantly. The tensile, flexural, and impact strength of the composite have been amended by 157.58%, 66.9%, and 16.5% with 1.5% addition of nanosilica in epoxy. Similarly, thermal conductivity of the composite is improved by 47.53% with the dispersion of 2.5% nanosilica in epoxy matrix. In addition, the thermal stability of the LES composite samples is substantially improved while disbanding nanosilica in epoxy matrix. However, the better results are reported for the LES composites containing 1.5% nanosilica content, compared to the next higher volume fractions of nanosilica content in epoxy matrix.

Development of a novel heat- and shear-resistant nano-silica gelling agent

Abstract The efficient and sustainable development of deep marine carbonate rock reservoirs in the Sichuan Basin has higher technical requirements for reservoir acidizing alteration technology. However, the acidification effect of deep marine carbonate rock reservoirs was hampered by the drawbacks such as uncontrollable acidification rate of the reservoir, the large friction resistance, and the great acid filtration. A novel heat- and shear-resistant nano-silica gelling agent CTG-1 is prepared based on nano-silica and combined with amide compounds. The influence of different factors on the acid filtration performance and heat- and shear-resistant capacity of carbonate rock reservoirs were analyzed, and then the mechanism of nano-silica gelling agent for acid filtration reduction in carbonate rock reservoirs is revealed. The research results showed that the filtration resistance of acid solution decreases slightly with the increase in the content of nano-silica gelling agent and reservoir pressure. The viscosity, fluid loss coefficient, and friction-reducing rate are as high as 25 mPa s, 2.4 × 10−2 m3 min1/2, and 71%, respectively, showing significantly better result than that of commonly used commercial gelling agents. The development of nano-silica gelling agent provides a reliable reference for effectively improving the acidification and stimulation effect of deep marine carbonate rock reservoirs.