Water Resistance Performance Research Articles

Acrylic Powder Modified Portland Cement

Abstract The key functions of polymer in modifying cement for both indoor and outdoor applications have been identified and demonstrated through years of practice since the early 1960s. The effectiveness of using pure acrylic polymer in cement modification can be credited to the unique acrylic chemistry in combination with special polymer designs and processes. Both acrylic powder and acrylic latex rely on the acrylic backbone to provide excellent performance and durability, especially for exterior applications. Acrylic redispersible powder recently developed preserves acrylic latex performance in mechanical strength, adhesion, and water resistance as demonstrated by various tests under wet- and dry-exposure conditions. In addition, use of acrylic powder as a “one-package” alternative to latex facilitates on-site handling, environmental protection, and reduces packaging and transportation costs. This paper presents the results of performance comparsion between acrylic redispersible powder and acrylic latex in cement modification. The polymer-modified mortar properties were evaluated and compared in both a typical concrete repair mortar and a ceramic tile formulation. The exterior durability of acrylic powder modified repair mortar was demonstrated through exterior exposure studies. The modification efficiency of acrylic powder was also studied at different polymer levels in a patching formulation that compared favorably to other commercial powders at lower polymer level usage.

南極昭和基地における防火建物建設のための石膏コンクリートの利用に関する基礎的研究

Some experiments are carried out on the basic properties of gypsum paste and concrete to investigate the usage of gypsum as a main material in constructing fire prevention buildings at Syowa Station in Antarctic. Inproved II-type gypsum anhydride, which is composed of 70 % II-type gypsum anhydride and 30 % sulfuric acid proof cement, is considered the most preferable binder for gypsum concrete at Syowa Station because of the special quality in the environment of low temperature and water resistant performance. Aggregate gathered at Syowa Station is to be used in concrete and we called it syowa station aggregate. Syowa station aggregate is similar to the mixture of crushed stone and crushed sand used in the interior and the fine-total aggregate ratio is constantly 60.7 %. Gypsum concrete using improved II-type gypsum anhydride and syowa station aggregate has good ability on manufacturing process such as mixing, casting and curing, high compresive strength and quick increase of strength. Then it is possible and effective to use the gypsum concrete in the construction of fire prevention buildings at Syowa Station.

Carotinoids as fat-soluble vitamine

Novel Ca-doped FeOx hollow microspheres were successfully prepared using carbon microspheres as templates. The as-prepared catalysts were characterized by FAAS, XRD, N2 adsorption/desorption, SEM, TEM, H2-TPR and XPS. The catalytic activities of the samples were evaluated by catalytic oxidation of 1,2-dichlorobenzene (o-DCB). The results showed that the molar ratios of Ca/(Ca + Fe) in the hollow microspheres and their morphologies significantly affected their catalytic performances. The low-temperature catalytic activity decreased in the order of FeCa10 > FeCa20 > Fe2O3 > FeCa5, in well agreement with the sequence of their reducibility. The optimal FeCa10 catalyst exhibited not only excellent catalytic activity, water-resistant performance and stability but also lower apparent activation energy (21.6 kJ/mol). In situ FTIR measurements revealed the acetate and formate species were the partial oxidation products, which could be subsequently oxidized to form CO2. It is concluded that the excellent catalytic performance of FeCa10 catalyst might be attributed to the combined effects of several factors such as small crystallite size, high surface active oxygen concentration, good low-temperature reducibility and the synergic effect between CaO and Fe3O4. It is reasonable for us to believe that such Ca-doped FeOx hollow microspheres are promising catalysts for the elimination of chlorinated volatile organic pollutants.