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Abstract This paper contributes to the expanding knowledge base on nanomaterial-enhanced cementitious composites, offering valuable insights for developing high-performance, sustainable concrete solutions. The study assessed the effects of three different types of nanomaterials—nano clay (NC), nano silica (NS), and nano cellulose (NCel)—on the compressive strength of high-early-strength concrete (HESC) through both experimental studies and a 23 factorial design. Incorporating nanomaterials into the HESC matrix led to a decrease in workability, with NCel demonstrating the least impact on this property across all studied replacement percentages. All HESC mixes containing nanomaterials exhibited higher compressive strength than the control mix (M mix) across all ages. The optimal percentages for compressive strength enhancement were 4.5% NC (33.43% increase at 3 days, 22.29% at 7 days, and 12.15% at 28 days), 4.5% NS (20.12%, 11.14%, and 4.89% respectively), and 0.0375% NCel (34.91%, 25.76%, and 13.46% respectively). The highest compressive strength was observed in the hybrid mix containing 4.5% NC and 0.0375% NCel, yielding strength enhancements of 35.7%, 26%, and 12.75% compared to the M mix. Statistical analysis indicated that nano cellulose had the most significant contribution to enhancing compressive strength, followed by nano clay. The mathematical models derived from the statistical analyses provide a reliable means of predicting the compressive strength of HESC at 3, 7, and 28 days based on nanomaterial content. Contour plots illustrated the optimization of compressive strength across different nanomaterial contents at each age. In summary, the findings underscore the potential of waste-derived nanomaterials to enhance the performance of HESC, paving the way for innovative waste utilization strategies in construction. The study emphasizes the importance of reducing curing times, improving structural durability, and minimizing the environmental impact associated with concrete production.

This paper contributes to the expanding knowledge base on nanomaterial-enhanced cementitious composites, offering valuable insights for developing high-performance, sustainable concrete solutions. The study assessed the effects of three different types of nanomaterials—nano clay (NC), nano silica (NS), and nano cellulose (NCel)—on the compressive strength of high-early-strength concrete (HESC) through both experimental studies and a 23 factorial design. Incorporating nanomaterials into the HESC matrix led to a decrease in workability, with NCel demonstrating the least impact on this property across all studied replacement percentages. All HESC mixes containing nanomaterials exhibited higher compressive strength than the control mix (M mix) across all ages. The optimal percentages for compressive strength enhancement were 4.5% NC (33.43% increase at 3 days, 22.29% at 7 days, and 12.15% at 28 days), 4.5% NS (20.12%, 11.14%, and 4.89% respectively), and 0.0375% NCel (34.91%, 25.76%, and 13.46% respectively). The highest compressive strength was observed in the hybrid mix containing 4.5% NC and 0.0375% NCel, yielding strength enhancements of 35.7%, 26%, and 12.75% compared to the M mix. Statistical analysis indicated that nano cellulose had the most significant contribution to enhancing compressive strength, followed by nano clay. The mathematical models derived from the statistical analyses provide a reliable means of predicting the compressive strength of HESC at 3, 7, and 28 days based on nanomaterial content. Contour plots illustrated the optimization of compressive strength across different nanomaterial contents at each age. In summary, the findings underscore the potential of waste-derived nanomaterials to enhance the performance of HESC, paving the way for innovative waste utilization strategies in construction. The study emphasizes the importance of reducing curing times, improving structural durability, and minimizing the environmental impact associated with concrete production. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the impact of nano-clay and nano-silica particles on the vibrational characteristics of composite cylindrical panels in corrosive environments. In this context, due to the presence of diluted sulfuric acid as the corrosive solution, the coupling effects of material degradation and hygroscopic loading on the natural frequencies are taken into consideration. In order to achieve this, it is first explored through experiment how adding nanoparticles affects the coefficient of hygroscopic expansion of the glass/epoxy specimens. Using this coefficient, the in-plane loading caused by corrosive solution is then applied in the equations. The mechanical properties and hygroscopic expansion coefficients of the composite samples exposed to the corrosive environment are first determined by certain experimental testing. The equations of motion are derived using the first-order shear deformation theory (FSDT), and the vibration problem is solved using the generalized differential quadrature (GDQ) technique. Investigation is conducted into the effects of various nanoparticles, immersion time, geometrical elements, and boundary conditions on the natural frequencies of the cylindrical panels. It is found that adding nanoparticles can significantly improve the mechanical properties, the corrosion resistance, and the natural frequencies of composites in which the nano-clay is more effective. For example, adding nano-clay and nano-silica particles, respectively, results in 32.32% and 26.29% increase in elasticity modulus of reinforced glass/epoxy composite. In addition, 12.71% and 47.32% improvements are observed in the natural frequency of the nano-clay reinforced composite panel before and after 90 days of immersion in sulfuric acid. In comparison, the nano-silica particles are responsible for 7.80% and 23.03% increase in natural frequency before and after immersion time. [ABSTRACT FROM AUTHOR]

Surface treatments applied to new or existing concrete elements provide effective protection against intrusive media, helping to reduce maintenance and repair costs. However, technical data are scarce on documenting the field performance of concrete surface treatments in cold regions with aggressive conditions, particularly for emerging nano-modified coatings. To address this gap, a field study was conducted to evaluate the efficacy of different plain and nanocomposites as surface treatments on 34-year-old concrete bridge deck sections in Winnipeg, Manitoba, Canada. The study compared neat resins (silane, methyl methacrylate, and ethyl silicate) and nano-based coatings (nano-silica 50 % solution, silane with nano-clay, and silane with nano-silica at 2.5 % and 5 % by mass) on cores extracted from cracked and uncracked concrete prepared with two surface preparation methods. The experiments compared the initial performance (transport properties and microstructural features) of coated concrete to its performance after one year under service conditions. The results indicate that coatings play a significant role in providing protection against intrusive media and reducing maintenance efforts and costs. Among the coatings tested, silane and methyl methacrylate offered the least improvement in concrete protection with time in cold regions. The 50 % nano-silica solution provided moderate performance, whereas ethyl silicate and silane nanocomposites demonstrated superior performance in reducing transport properties regardless of the surface preparation methods. Given the improvement in long-term durability and cost, silane nanocomposites with a 2.5 % loading ratio may be a viable treatment method for concrete flatwork in cold regions.

Introduction. Many research had worked on improving the performance of concrete subjected to severe environment and improve concrete corrosion resistance. Using nano-materials is one of the methods had been used recently to improve concrete properties. In this research, a comparison between the performance of nano-silica and nano-clay in enhancing the durability properties of concrete was investigated. Methods and Materials. The experimental program was carried out through examining water absorption, water permeability, rapid chloride penetration test, corrosion resistance, bond strength of steel rebar before and after subjected to corrosion, and finally microstructure test. Nano-silica and nano-clay were added at 1%, 3%, and 5% as a partial replacement by weight of cement. Results. Both nano-silica and nano-clay showed significant performance in reducing the permeability and porosity of concrete and improve corrosion resistance of concrete. For comparison, nano-clay had a significant impact than that of nano-silica on concrete properties; in which the water permeability resistance of nano-clay mixes was enhanced by 87% than that of the control mix, while for nano-silica, it was 51% only. The chloride ion penetration was reduced by 72% for nanoclay mixes, while in nano-silica was 28%. Discussion. Nano-clay had a significant effect than that of nano-silica on the concrete durability properties; the flat-shaped of nano-clay particles had improved the microstructure of the cement matrix through the damping effect, besides the filling effect through the microstructure of the matrix which reduces the chloride ion penetration and improves water absorption and permeability of concrete. Conclusion. The optimum percentage of nano-silica is 1% by weight of cement as a partial replacement of cement by weight. However, for nano-clay is 5%, which gives the best performance in improve the durability properties of concrete.

Adding nanomaterials to concrete extends the size range of constituent particles well into nano-scale dimensions, which could help the compacting of particles in cement-based materials. Regarding the differences between shotcrete and cast concrete, in this study, the properties of shotcrete with nano and micro-silica and nano-clay were experimentally studied. The micro and nanomaterials have been added at different percentages (6%, 9%, and 12%) to a shotcrete paste. The comparison was based on the uniaxial compressive strength, flexural strength, tensile strength, and porosity tests of different specimens. The results indicated that the maximum increase in compressive, flexural, and tensile strengths of shotcrete was related to 12% nano-SiO2, while for 12% nano-clay, all of these strengths were decreased at 28 days. The optimum percentage for shotcrete substitution by nano-clay was established to be 6%. Also, the application of the nanomaterials led to a decrease in the water absorption and porosity of shotcrete. Eventually, the results revealed that the improvement of mechanical properties by the introduction of the nanomaterials in shotcrete could be satisfactory.

This study aimed to investigate the impact of adding clay and silica nanoparticles (NPs) on the swelling and thermal properties of low-density polyethylene (LDPE) composite. The migration of nano-clay and nano-silica into food simulants (distilled water, acetic acid 3% and ethanol 95%) was examined within 10 day storage at 40 ℃. It was found that adding NPs into composites could increase the swelling index, mainly in acetic acid 3%. The nanocomposites' thermal properties changed after migration, and crystallinity degree of nanocomposite diminished due to migration of NPs from the film. The migration of aluminum (Al) and silicon (Si) NPs into ethanol 95% was generally higher than migration into acetic acid 3%. Thus, NPs from this type of nanocomposite are more likely to migrate into foods with high fatty acid contents than into aqueous foods. [ABSTRACT FROM AUTHOR]

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This research article reports, the preparation of thermoplastic vulcanizates (TPVs) and TPV nanocomposites (TPVNs) based on EPDM and polypropylene (PP). New generation ultra‐high molecular weight EPDM (UHMW‐EPDM) and PP with nano‐fillers (nano‐clay and nano‐silica) and has been studied and characterized extensively typically for automotive applications. This special type of UHM‐EPDM‐based TPVs exhibit superior physico‐mechanical properties over conventional EPDM‐based TPVs and in the presence of nano‐fillers, they show even better physical properties. The TPVNs were prepared with a fixed EPDM: PP ratio and the nano fillers were varied at different concentrations. The influence of nano‐fillers, especially hectorite nano‐clay and nano‐silica has been first explored through physico‐mechanical properties. Tensile strength, elongation at break, and modulus at various strain are improved for nano‐filler filled TPVNs. We have observed that due to the incorporation of nano‐fillers into the TPV matrix, swelling has been decreased. From morphology (AFM, SEM) study, it is observed that the fillers are well dispersed in the TPV matrix and nano‐silica fillers are well dispersed than nano‐clay (hectorite). Furthermore, small‐angle X‐ray scattering (SAXS) studies have also been pursued to get a better insight into the TPV system. These newly developed TPVs can be used as potential candidates for application in the automotive sector. [ABSTRACT FROM AUTHOR]

Ultrafine nano-silica particles can improve the hydration process and concrete performance due to its high surface area and potent reactivity, which may be utilized to counteract the adverse effects of cold temperatures. In the current study, five nano-modified concrete mixtures were prepared to investigate the effect of a curing freezing temperature (−15 ℃) on their mechanical and physical properties, durability, and microstructure features. All mixtures comprised calcium nitrate-nitrite as a cold weather admixture system (CWAS) to depress the freezing point of mixing water. In addition, nano-silica or nano-clay powders impregnated with phase change material (PCM) were added to the mixtures as internal curing nanocomposites. All mixtures were cured at − 15ºC to simulate winter conditions in cold regions. The mixtures' performance was assessed based on setting times, 7 and 28 days compressive strengths, fluid absorption, and resistance to frost damage in water and salt solution. Furthermore, thermogravimetry, scanning electron microscopy associated with energy-dispersive X-ray spectroscopy, and mercury intrusion porosimetry were performed to assess the hydration, microstructural development, and pore structure features of the produced concrete, respectively. The coexistence of nano-silica and CWAS with the nanocomposites, especially in the case of nano-silica powder as a host for PCM, markedly improved the overall performance of concrete. This highlights the promising use of nano-modified concrete cured internally with nanocomposites for cold weather construction applications (down to −15 ℃), without the need for heating practices. • Using nano-siliUsing nano-silica in concrete is better relative to nano-clay as a host to PCM to produce internal curing aid nanocomposites. • Leakage of PCM resulted in delayed concrete skeletal rigidity, lower mechanical capacity, and reduced durability. • Nano-modified concrete protected by the hybrid system achieved a mutual balance of early-and-late ages performance. [ABSTRACT FROM AUTHOR]

Highlights • The hybrid-NS/NC-nano-particles enhance the hydration-kinetic of composite cement. • NS:NC hybrid system has a remarkable impact on compressive strength. • Increase in gel/space ratio reduces porosity yielding high compaction of hardened cement matrix. • Microstructure of hybrid-nano-particles densified the matrix with the absence of portlandite. • 3%NS:3%NC hybrid-nano-particles is the optimum composite which gave the highest performance. Abstract This study evaluates the synergistic impact of nano-silica (NS) and nano-clay (NC) on the hydration characteristics and microstructure of ordinary Portland cement (OPC) paste. Two main parameters, which strongly affect the physico-chemical and mechanical performance of OPC-pastes, including the hybrid NS and NC mass% (0, 1, 2, 4 and 6 wt% at NS:NC mass ratio of 1:1) and superplasticizer (SP) content, SP% (0 and 1 mass% with respect to OPC) have been studied. The results proved the addition of hybrid NS/NC has a good impact on the performance of OPC-pastes. All NS/NC-cement composites containing 1% SP showed the highest engineering properties comparing with composites with no SP. The composite containing the hybrid effect of 3 wt% NS:3 wt% NC:1 wt% SP presented the highest performance at all ages of curing as confirmed by X-ray diffraction, thermal analysis and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

Alkali-activated slag (AAS) concrete could be considered as an environmentally friendly and economical concrete. The aim of this study was to investigate the effect of nanoparticles including nano-silica, nano-alumina, and nano-clay on the resistance of AAS concrete against freeze and thaw cycles. Sodium hydroxide and sodium silicate were used for the activation of slag in AAS concrete. In this investigation, a control mix without nano materials and 3 mixes containing 1, 2 and 3 wt% of nanoparticles were prepared. Samples were tested by the freezing-thawing test, according to the ASTM C666 -B standard. The compressive strength and mass loss of AAS concrete specimens were measured. The results showed that nano-silica and nano-clay, respectively, performed better than the nano-alumina in improving the strength and durability of alkali-activated slag concrete subjected to freeze and thaw cycles. Adding 2% and 3% of nano-silica had a marginally smaller effect on AASC properties compared with 1% nano-silica. [ABSTRACT FROM AUTHOR]

• NC has greater effect on fresh properties of glass mortar than nS. • NS/nC can refine the pore structure and lead to denser microstructure of mortar. • Little nC can improve the 28-day compressive strength greatly of glass mortar. • The addition of 1% nS/nC have similar effect on suppressing drying shrinkage. • The additional use of 1% nC suppressed the expansion by 43.6% at 28-day. Nowadays, nano materials were proved to be able to improve the properties of mortar, especially for recycled mortar with poor properties. In this study, nano-silica (nS) and nano-clay (nC) were used in waste glass mortar, with an additional amount of nS or nC varied from 0% to 6% of binder content by weight. Waste glass cullet was used as fine aggregate to fully replace natural sand in waste glass mortar. The properties of fresh and hardened waste glass mortar with or without nS/nC, including the early stiffening, flowability, density, compressive and flexural strength, shrinkage and alkali-silica reaction, were experimentally examined in this study. In addition, the pore size distribution of waste glass mortar was studied by using the mercury intrusion porosimetry test to build the relationship between microstructure and macro properties. The results show that nC has a greater effect on the early stiffening and flowability of mortar than nS. The defining pore structure and denser microstructure lead to the higher density and mechanical properties of mortar with nS/nC. nC is more beneficial for improving the 28-day compressive strength of glass mortar at a very small amount, whereas, the effect of nS on the strength at early ages of glass mortar is clearer. The incorporating use of 1% nS/nC have similar effect on suppressing the drying shrinkage but quite different influence on the ASR expansion. The additional use of 1% nS can increase the ASR expansion of glass mortar while 1% nC suppressed the expansion by 43.6% at 28-day. [ABSTRACT FROM AUTHOR]