One of the most important requirements for the manufacture of refractory mortars, especially those used in the construction of thermal systems (building or plastering), is the balance between thermal insulation properties and porosity. Where, increasing porosity of mortar to a large amount may be always undesirable, because the absorption of liquid and gases emitted from industrial system is decline the bonded with bricks and structural properties of mortars. Refractory mortars prepared from either fired bauxite or metakaolin clays with different percentages of kaolin (10, 20, 30, and 40 wt%). Bauxite rocks were fired at 1200 °C and metakaolin was obtained by firing kaolin up to 700 °C then crushed and grinded. Grog was added to mixture to reduce the shrinkage. Cylindrical specimens are prepared and then sintered at 1200 °C. All mixtures maintained a low thermal conductivity within the limits of thermal insulation material (less than 0.5 W/m K); it was done by controlling the porosity which reached a maximum value approximately 25%. The volumetric heat capacity and thermal diffusivity was ranged between (1-10 MJ/m 3 K), (0.06-0.2 mm 2 /s), respectively.
Generally, the major problems of moisture damage are caused by wetting, and particularly in construction, which has led to extensive research for the production of hydrophobic (anti-wetting) coatings. The aim of this research is to prepare an anti-wetting (hydrophobic) nanocomposite coating for different construction surfaces (ceramic, brick and gypsum). Hydrophobic nanocomposite coating was synthesized using electrospinning technique. Polymethyl methacrylate and polystyrene (PS) solutions were prepared in different ratios and then separately reinforced with ZrO2 and ZnO nanoparticles. Contact angle, surface roughness, surface free energy and weathering effects were calculated for all specimens after being coated. All previously selected materials surfaces showed superhydrophobic and hydrophobic properties. The best results were obtained on ceramic surfaces after coating with PS/ZrO2. The water contact angle was 153° while the surface roughness was 0.491 µm and also showed the lowest surface free energy which was 5.5 mJ/m2. Weathering conditions tend to decrease the values of contact angle and this is due to the environmental effect of the weathering but they still have their hydrophobic properties. SEM test was used to determine the surface morphology and nanoparticle size for ceramic surfaces coated with PS and nano-ZrO2.
The properties of concrete are affected by various factors, some of which affect its strength and others affect its hardening. Curing methods are among the main factors that greatly affect the setting time and the speed at which it gains strength. In this study, heat curing was used to increase the speed of polymer concrete strength gaining. The mechanical behavior was investigated under two heating conditions (1 and 2 hours a day for a week) for unsaturated polyester polymer concrete specimens. Results showed that 87% and 90% of the compressive strength at 28 days are obtained after 4 days of 1 hr. and 2 hrs. of heat curing respectively, while 89% and 91% are obtained after 7 days of 1 hr. and 2 hrs. of heat curing respectively. In contrast, 86% and 93% of the splitting tensile strength at 28 days are obtained after 4 days of 1 hr. and 2 hrs. of heat curing respectively, also 90% and 94% are obtained after 7 days of 1 hr. and 2 hrs. of heat curing respectively
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