Mechanical and durability properties of concrete structures, including concrete pavements, have been a focus of attention. In this regard, the potential of nanomaterials needs to be discussed more. Water permeability, abrasion, and compressive strength are assessed in this study. So far, the incorporation of diverse types of nanomaterials with different methods has caused the enhancement of some mechanical and durability properties of concrete. In the present study, five types of nanoparticles as nanoSiO2, nanoTiO2, nanoAl2O3, nanoFe2O3, and nanoFe3O4 in different amounts were uniformly dispersed and added to the concrete. To reduce the cost and decrease the required nanomaterials, specimens were made in two layers. The surface layer of specimens was made from self-compacting concrete containing nanoparticles with 1 cm depth, which was placed over the bottom layer from conventional concrete with different depths depending on the tests. The test results indicated that the properties of concrete pavements containing nanoparticles are improved comparing to the control specimen. For instance, in specimens containing nanoTiO2 as much as 3% by the weight of cement, the water permeability improved by 84. 6%. Furthermore, the abrasion resistance of specimens containing nanoSiO2 at an amount of 1% was enhanced by 88. 1%, and the addition of 3% of nanoSiO2 raised compressive strength by 88%.

Lead-free (Ba0. 85Ca0. 15)(Ti0. 9Zr0. 1)O3 piezoceramics with nano SiO2 additive were prepared by conventional solid oxide sintering method. The samples were fabricated by means of cold isostatic pressing and sintering was performed at 1350 ° C for 4 h in the air. The phase structure and microstructure were studied via X-ray diffraction technique and field emission scanning electron microscopy. The room-temperature dielectric properties and the variations in the temperature ranging from 23 to 160 ° C were measured using a high-precision LCR meter. The mechanical properties such as Vickers hardness and compressive strength were investigated. The obtained results showed that nano SiO2 addition produced dense and uniform microstructures with larger grains than pure BCZT. The Curie temperature of undoped BCZT increased to about 25 ° C through the incorporation of 0. 75 mol% SiO2 and then, the mechanical properties considerably improved. Accordingly, BCZT piezoceramic with nano SiO2 additive enjoys viable properties, which makes it widely applicable.

In the present study, the sedimentation mechanism of SiO2 nanoparticles (NS) on Graphene Oxide (GO) nanosheets by hydrolysis of Tetra Ortho Silicate (TEOS) in water/ethanol solution was investigated. In the first part, the possible interactions among nanoparticles by UV-Vis and Transmission Electron Microscopy (TEM), and in the second part, the mechanical properties of nanocomposite materials contain NS and GO (NS&GO) by molecular dynamic simulation (MDS) were discussed. Finally, the application of single and hybrid nano materials on 12 kinds of the mixture of mortars containing natural pozzolan was compared with mechanical properties. the improvement of dispersion of NS on GO nanosheets was visible in TEM. Also, the results of MDS demonstrate 75% increase in tolerable stress and 250% increase in Young’s modulus in nanocomposite compared with single Nano-SiO2. 28-day compressive and tensile strength mortars containing NS&GO increased by 31% and 100%, respectively and compared with the control. As a result, appropriate dispersion and distribution of nanoparticles, NS&GO through nucleation properties, and zeolite through pozzolanic properties improved the mechanical function of mortars.

Background and objectives: Waste paper recycling has grown as an industry in Iran and the world and offers many benefits to the environment and humans. Municipal waste is also reused after recycling processes. Cardboard recycling industry has great environmental and economic importance and with the lack of wood resources and high demand for paper products, it plays an important role in the development of paper-related industries. However, recycling can be associated with a reduction in the optical properties of the paper. The use of nanoparticles in the paper industry is also expanding day by day. Nanosilica is one of the most important nanoparticles used as a retention aid in the paper industry. In order to reduce the consumption of long fibers and obtain the desired optical properties, the use of nanosilica alone or in combination with other materials such as cationic starch and cationic polyacrylamide is investigated. The purpose of this research is to compare the effect of separate and combined use of nanosilica additives, cationic polyacrylamide, cationic starch and long fibers on the optical properties of white liner paper pulp.Methodology: In this study, white paper pulp with a brightness of at least 78% and a gloss of at least 45% was used to prepare handmade papers. Long fiber chemical paper pulp from coniferous kraft imported from Russia with a brightness of 89% was used in the laboratory. Nanosilica powder (NanoSiO2) produced by Degussa, Germany, cationic polyacrylamide with Farinret K325 brand, produced by Degussa, Germany, and cationic starch from LyckebyAmylex, Slovakia, were used. Independent treatments include the addition of 10% refined long fibers paper pulp, 6% nanosilica, 1.5% cationic starch and 0.15% cationicpolyacrylamide and combined treatments include 6% nanosilica and 1.5% cationic starch and 6% nanosilica and 0.15% cationic polyacrylamide. Then 127 g.m-2 handmade papers were prepared and their optical and microscopic properties were evaluated.Results: The results showed that by adding 10% of long fibers, the brightness decreased and by using 6% of nanosilica, the maximum brightness was obtained. Meanwhile, the whiteness of papers with 6% nanosilica was minimum and maximum with 0.15% cationic polyacrylamide. Opacity showed its highest value with the combination of 6% nanosilica and 0.15% cationic polyacrylamide. Also, by increasing the amount of polyacrylamide and cationic starch, individually or in combination with nanosilica, the opacity increased. The light absorption coefficient was the lowest in papers with 6% nanosilica and the light scattering coefficient was the highest in papers containing 6% nanosilica and 0.15% cationic polyacrylamide. A colorimeter was used to measure the color components and the results showed that the additives had an effect on the brightness and whiteness of the papers. Also, changes in the color spectrum and the amount of color change were also observed. Additives increased the darkness and changes in different colors.Conclusion: The use of nanosilica separately and in combination with starch and cationic polyacrylamide increases the brightness of papers. Also, the use of cationic polyacrylamide separately and in combination with nanosilica leads to an increase in the whiteness and opacity of papers. The brightness factor of the papers, which is representative of the L* component, decreased with the exception of the addition of 10% long fibers and 6% nanosilica. The amount of overall color change with ∆E* was the lowest in samples containing 1.5% cationic starch and the highest in samples containing 0.15% cationic polyacrylamide. The use of some treatments can lead to a decrease in the optical properties and a decrease in the printability quality of the white liner. To solve this problem, mechanical paper pulp that has been decolorized or coated on the surface of the paper can be used. The presence of nano-silica particles in the structure of the paper improves the bond surface and reduces the prosity, which results in the reduction of surface roughness and less light refraction, and increases the light reflection and brightness of the paper.