With the growing progress in the use of concrete, novel technologies have been introduced into the production of this building material. Self-consolidating concrete (SCC) is one of the concrete types, which has been extensively applied in building industry nowadays. SCC could be empowered in terms of durability and mechanical properties and, as a result, the service-life of SCC and efficiency of concrete structures could be increased using complementary materials such as Pozzolans and NANO-materials. Considering their structures, NANO-materials such as NANO-silica, NANO-calcium carbonate and other similar materials could be helpful in making SCC. This paper aims to investigate the effect of NANO-calcium carbonate and NANO-silica on the durability and mechanical characteristics of SCC. Thus, different concrete forms with the mixture designs containing 0%, 1%, 2% and 3% NANO-calcium carbonate and NANO-silica were developed. The samples were made in 15*15*15 cubic and cylindrical forms, depending on the experiment type, and tested at the ages of 7 and 28 days. In all the mixture designs, the rheological tests relating to fresh concrete including concrete flow, slump test, V-funnel, L-box, J-ring and U-box tests were performed. Finally, in order to examine the durability, permeability, freeze and thaw cycle, electrical resistance and pulse rate determination in concrete were employed. At the end, micro-structural properties of concrete containing NANO-carbonate were tested using XRD and SEM tests. In all the samples, use of NANO-calcium carbonate increased durability and resistance properties of SCC.

NANOcomposite gears based on Polyamide 6/Polypropylene (PA6/PP 67/33) blend containing 2.5 to 10 (wt%) of NANO-CACO3 and 5 (wt%) of maleated polypropylene (PP-g-MAH) as compatibilizer were prepared by injection molding. The wear and temperature of gears were characterized against the time by employing a gear testing rig. The ends of gears working lives at which the permanent deformation was happened and, as a consequence, power transmission interrupted, under output torque 14.8 Nm were obtained. The inclusion of NANO-CACO3 led to the 5oC reduction of gears working temperatures. The maximum life under the torque of 14.8 Nm, was observed in NANOcomposite gears containing 2.5 (wt%) of NANO-CACO3 was nearly 2.5 times higher than that of neat PA6 gears. The raise of gears durability by inclusion of CACO3 NANOparticles was attributed to the improvements of gear teeth flexural and wear resistances.

NANOparticles and NANO-reinforcement are extensively used in geotechnical engineering and there are various reports on the effect of NANOmaterials on the improvement of the engineering properties of various soil types. The effect of NANO calcium carbonate (NANO CACO3) on the geotechnical properties of sandy clay (SC) soil containing different levels of clay was investigated. To this end, three types of SC soil containing 10, 20, and 30% clay and 0. 3, 0. 7, 1. 1, and 1. 5% NANOparticles were cured for 7, 14, and 28 days and then placed under uniaxial compression test. Also, the experimental results were numerically analyzed by group method of data handling (GMDH) using an artificial neural network. The samples were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests. According to the results, adding NANO CACO3 to SC soils, caused an increase in the uniaxial compressive strength and secant modulus. Moreover, the compressive strength obviously increased over time. An optimum NANOparticle level of 0. 7% was obtained for the soils containing 20% and 10% clay. The corresponding NANO CACO3 level for the soil containing 30% clay was 1. 1%. The effect of NANO CACO3 as an effective additive on the ultimate compressive strength of the soil was investigated by XRD and SEM evaluations. The results indicated an increase in the crystallinity of particles after adding CACO3 NANOparticles. Finally, based on numerical analysis of the experimental result, a correlation was obtained to predict the uniaxial compressive strength of the improved SC soil with a mean error of 4%.

NANOcomposite gears based on Polyamide 6/Polypropylene (PA6/PP 67/33) blend containing 2.5 to 10 phr of NANO-CACO3 and 5 phr of maleated polypropylene (PP-g-MAH) as compatibilizer were produced by injection molding. The morphology was studied using scanning electron microscopy. The wear and temperature of gears teeth as well as gears working lives were characterized by employing a gear test rig under two different output torques including 8.9 and 14.8 Nm. In all experiments, the teeth’s temperature and wear values for driver gear were higher as compared to those of driven gear. The incorporation of 2.5 and 5 phr NANO-CACO3, led to the reduction of temperature and wear rate of gears. The wear rates of gears containing 2.5 phr of NANO-CACO3, under the torque of 8.9 and 14.8 Nm, were 60 and 83% lower than those of neat PA6 gears respectively. The maximum gear life under the torque of 14.8 Nm (63000 revolutions) was observed in NANOcomposite gears containing 2.5 phr of NANO-CACO3 which was nearly 200% higher than that of neat PA6 gears (21000 revolutions). The raise of Polymer based gears performances as a result of CACO3 NANOparticles inclusion may be attributed to the improvements of gear teeth flexural, wear and heat resistances.

In this study, polyamide 6 (PA6)/ nitrile butadiene rubber (NBR) based hybrid-NANOcomposites reinforced with calcium carbonate and organo-clay as NANOfillers in various content of 1, 3 and 5 phr were prepared and characterized. The NANOcomposite samples were prepared through the melt processing method in an internal mixer. The effect of rubber phase (NBR) content (10, 30, and 50 wt. %), calcium carbonate content (1, 3, and 5 phr), and organo-clay content (1, 3, and 5) was investigated on morphology and mechanical properties of the NANOcomposites. The mechanical properties were evaluated by tensile, flexural, and Charpy impact tests. The results showed that adding the NBR reduces the tensile strength, tensile modulus, flexural strength, and flexural modulus, and increases the impact strength. Introducing the NANO-clay and calcium carbonate improves the tensile and flexural strength, tensile and flexural modulus, and decreases the impact strength. The NANO-clay content from 1 to 3 phr improved the impact strength.

In this paper, the effect of TiH2 and CACO3 blowing agents was investigated on the structure and energy absorption of Al-7%Si-3%SiC composite metal foam by powder compact route. Composition of the foam was prepared from a mixture of Al, SiC and Si powders. Then, precursors were consolidated in H13 die mould by cold and uni-axial pressing at 110 MPa and at room temperature. The pressed precursors were extruded at 500oC, in a 12*24 mm2 cross-section. Then, the precursors were foamed in a 316L-stainless steel tube with diameter and height of 20 mm and 100 mm, respectively, in an electrical resistance furnace. Finally, for micro-structural investigation the samples were cut and polished, and a scanning electron microscope was used to observe the cell wall and surface topology. For calculation and comparison, energy absorption was used in an Instron Hydraulic test machine and the foam samples were compressed at the ramp velocity of 50 mm/minute. Results showed that foams with CACO3 agent due to having high porosities are more stable than foams with TiH2 agent. Also, the energy absorption for foam with CACO3 agent is more than foams with TiH2 agents. However, its drainage due to less thickness of wall porosities is better than the foam with CACO3 agent.

The materials that are now being used in the conservation of historic and cultural heritage are originally available in the market of industry. Recently, some of the materials are improved in the fields of conservation of heritage and they are so common in the consolidation of artificial objects or monuments. The aim of the study is identification of the proper material for consolidation of beige stone against environmental factors. Thus, three materials were chosen from the recent products which are more compatible with composition of limestone. Stone specimens were consolidated with NANO Estel (NANOstructure silicon dioxide SiO2 dispersion in water), NANO Lime (Ca(OH)2) (NANO-lime dispersion in isopropyl alcohol), and Dibasic ammonium phosphate ((NH4)2HPO4) well known as HAP method. Samples were characterized by FE-SEM and tested by Microdrilling resistance. The porosity also was analyzed by MIP. The results show NANO-lime has the lowest surface effectiveness which barely changed the physical properties of the stone in comparison with the others. In the case of covering, in both Estel and HAP, some microcracks (with branch and net pattern) were observed on the layer above substrate, in contrast, NANO-lime made a homogeneous layer. Also, NANO-lime treatment caused 6% reduction of the porosity which had the most effectiveness on stone porosity. J. Color Sci. Tech. 12(2018), 1-12© . Institute for Color Science and Technology.

In this study, Al/NANO-MgO composites were produced via vortex method (direct incorporation). MgO NANOparticles with 60-80 nm diameter (as reinforcement) and Al-356 (as metal matrix) were used for production of these composites. The molten composites were stirred, and then cast into a metallic mold. The effects of MgO volume percent with 1.5, 2.5 and 5%, and casting temperature (various temperatures, viz. 800, 850 and 950oC) on mechanical properties of composites were investigated. Results show that mechanical properties of samples have increased significantly compare to matrix metal. In this regard, the best compressive strength and hardness results were obtained in the specimens containing 1.5 and 5 vol% NANO-MgO produced at 850oC (which are 896 MPa and 73 HB), respectively.