Le bloc autobloquant.Description du sujet. Influence de la bio-calcification sur la rsistance en compression des blocs autobloquants base de sol-ciment. Le dbut des annes 1990, en Russie et dans les autres pays de l'ex bloc de l'Est, est en effet caractris par une srie de problmes sociaux et conomiques qui vont parfois susciter la nostalgie : le taux de corruption est lev, la mafia. Lutter contre des gangs de motards comme les Posse, les Rock Machine et les Hells.Dans les annes suivant la chute du rgime, le rock se fait dfenseur de l'idal communiste la suite des dsillusions de la jeunesse. Dun rythme hip-hop, &224 un hymne disco, chaque chanson offre des paroles d&233 cal&233 es et un air accrocheur.Influence de la bio-calcification sur la résistance en compression des blocs autobloquants à base de sol-cimentTranslations in context of bloc rock in English-French from Reverso. Le Rock des Blocs est une s&233 rie danimation unique qui invite les enfants &224 danser et chanter, dans une ambiance aussi joyeuse que color&233 e Chaque &233 pisode nous fait d&233 couvrir un personnage unique en forme de bloc qui chante sa propre chanson.
Des bactéries du sol, Bacillus pasteurii KCTC 3558, et micro-organismes efficaces (EM) ont été ajoutés en remplacement de l'eau dans le bloc avant de le modeler. Cette étude a été conçue pour étudier l'effet de bio-calcification sur la résistance à la compression du bloc autobloquant en sol-ciment.Méthode. Cependant, il n'existe actuellement aucune recherche sur l’influence de l’application de la bio-calcification ou de la précipitation de calcite induite biologiquement sur la résistance en compression du bloc autobloquant.Objectifs. Bon nombre de recherches sur le mélange de matériaux alternatifs pour la fabrication de blocs autobloquants sont menées afin d'améliorer sa résistance en compression.
Interlocking block is an environmental friendly construction material because during its manufacturing process, less energy was consumed and almost no carbon dioxide is produced. It can be used for all types of building from wells, houses to schools and resort buildings. Our results showed that microbiologically induced calcite precipitation could help increasing the compressive strength of soil-cement interlocking block.1Interlocking block is a common construction material which was used as the building blocks for many civil structures. Calcium carbonate crystals were also observed under scanning electron microscope which suggested that an increased compressive strength of interlocking block was caused by biocalcification.Conclusions. At 28 days, the compressive strength of interlocking block supplemented with B. pasteurii KCTC 3558 and 5% EM were 7.38% and 9.79% significantly higher than control. The change of compressive strength in interlocking block at 3, 7, 14 and 28 days of incubation was determined.Results.
Le Rock Des Blocs Trial Wastes Can
During this process calcium carbonate accumulates due to the activity of urease-producing microorganisms (Douglas et al., 1998 Hammes et al., 2002).4Calcium carbonate precipitation occurs in nature when the concentration of calcium ion, and/or carbonate ion increases. Many industrial wastes can be used as supplement for interlocking block production such as coconut shell ash from power plants that use coconut shell coal as fuel, blast furnace slag which is a waste generated from steel industries, molten slag from burning refuse in fluidized-bed gasification furnace (Hosokawa et al., 2004), silica fume from silicon metal industries (Thailand’s Department of Industrial, 2012) and kaolinite top soil from kaolinite mines (Kokkhamheang et al., 2008).3Biocalcification also known as microbiologically induced calcite precipitation (MICP), is a normal biochemical process that naturally occurs in many environments such as sea water, fresh water and soil. Interlocking blocks can be divided into two types based on its raw materials: soil-cement block, a soil based block which was used in this study and a concrete block, in which the major component is cement.2Production of interlocking block using industrial waste as supplementary material in order to improve some qualities has been reported.
In addition, some ureolytic bacteria were able to improve the properties of concrete such as increased compressive strength (Ghosh et al., 2005 Ramakrishnan et al., 2005) and decreased permeable property. Calcium carbonate precipitation occurs when Ca 2+ is present in the environment.6There are reports on the use of biocalcification for repairing the surface of the stone and cement concrete (Stocks-Fischer et al., 1999 Ramachandran et al., 2001). The utilization of urea results in an increasing of the environment pH which causes calcium ions and carbonate ions to precipitate in form of calcium carbonate according to the following equations:5Urease hydrolyzes urea to carbonate and ammonium ions that increase the pH in an environment.
Scanning electron microscope was also used to detect calcite precipitation within the interlocking block. Compressive strength was determined using standard method. The comparison was done between Bacillus pasteurii KCTC 3558, a known urease producer, and effective microorganisms (EM). This study was designed to investigate the influence of microbial induced calcite precipitation on the compressive strength of soil-cement interlocking block. However, to the best of our knowledge, no research on using MICP to improve the strength of soil-cement interlocking block has been reported. Recently, urease producing bacteria was used for concrete strength improvement and as concrete deteriorating mold inhibition agent (Park et al., 2012a).7All previous reports mentioned above demonstrated that biocalcification could be used to improve the properties of concrete and brick.
(1993) containing yeast extract (0.5 g·l -1), (NH 4) 2SO 4 (2.6 g·l -1), MgSO 4.7H 2O (1 g·l -1), NiSO 4.7H 2O (0.032 g·l -1), KH 2PO 4 (2.4 g·l -1), K 2HPO 4 (5.6 g·l -1), CaCl 2 (0.3 g·l -1), urea (10 g·l -1) at 37 ☌ on rotary shaker (150 rpm) for 24 h in order to obtain an approximate cell density of 5.5 x 10 6 CFU·ml -1 without transferring culture into new fresh growth medium. Bacillus pasteurii KCTC 3558 was cultured in production media modified after Smith et al. They were used as the source of urease in this study. Effective microorganism was purchased from EM Kyusei Company Limited, Chiang Mai, Thailand. Microorganisms8 Bacillus pasteurii KCTC 3558 was obtained from Korean Collection for Type Cultures (KCTC).
The cement to soil ratio was fixed at 1:6 (by weight). Red earth was sieved through 4 x 4 cm 2 grid prior to manufacturing process ( Figure 1a). Microbial calcite deposition in interlocking block9Three sets of 40 blocks of soil-cement interlocking blocks were made from local factory in Chiang Mai province, Thailand which were:10– soil-cement interlocking block without added bacteria (control) 11– soil-cement interlocking block with B. pasteurii KCTC 3558 in urease production media 12– soil-cement interlocking block with urease production media + 5% (v/v) EM added as replacement for mixing water.13Portland cement type I and red earth were used for interlocking block production.
Surface of the block was capped with quick-hardening cement and the cap was aged for at least 24 h prior to a compressive strength test. Each block was dried overnight and weighed. Five blocks from each set were sampled and tested for compressive strength at 3, 7, 14, and 28 days of incubation. After 28 days of incubation, color and appearance of the surface of interlocking block were observed.14Compressive strength measurement was carried out according to standard method of ASTM C 67- 07 (American Society for Testing and Materials, 2007). All sets of interlocking block were sprayed with water and moist incubated indoor under plastic sheet for up to 28 days ( Figure 1d). The resultant mixture was molded in 12.5 x 25 x 10 cm 2 mold in hydraulic compressing machine ( Figure 1c).
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