Biodegradation Mechanism of the Superfine Fibers-Cement Composite

Kazunori SHIBANO*, Shuji YOSHIZAWA and Yuu OGAWA

Institute of Technology, Tokyu Construction Co. Ltd; 3062-1, Soneshita, Tana, Sagamihara-shi 229-1124 Japan
Department of Chemistry, Meisei University; 2-1-1 Hodokubo, Hino-shi 191-8506 Japan

Natural fibers of cellulose and collagen were immersed in water and ground into submicron sized peices using a grinder equipped with grindstones.
Biodegradable superfine fibers-cement composite was prepared by mixing the superfine fibers and cement was studied. The composite was degraded in soil after several months to decay collapsed into sand. The composite buried in soil was biodegraded from the outer side of the sample by action of bacteria and mold. From DTA-TG, it was suggested that Ca2{ migrated from the centeral part to the outer part of the sample. The biodegradation mechanism of the composite was suggested as follows; (1) The reaction of carbon dioxide evolved by metabolism of the bacteria with free Ca2{ in the composite afforded CaCO3, (2) Ca2{ in the central part migrated to the outer part due to lowering Ca2{ concentration in the outside. The superfine fibers were finally biodegraded to water and carbon dioxide.

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