The Study Of Pouring And Construction Technology On Precast Concrete Elements Of Eco-revetment

Precast stepped concrete eco-revetment as a new precast concrete elements arefrom Japan, these concrete structures use the method of first molding, without anydecoration, and belong to fair-faced concrete. In its natural state and well-designedconfiguration as forms of expression, being used in municipal river-restorationproject. Compared with the traditional methods of revetment, which have obviousadvantages in durable, ornamental, environmental and economic performance.However, due to special structure of molds and limits concrete shaping, manyproblems of concrete materials and performance exist, Pouring and vibrationtechnology, Selection of mold release agents and brushing are still unreasonable,resulting in poor appearance quality, seriously affecting the use of eco-concreterevetment, ornamental and durability. To solve these problems, article is studied andanalyzed:Precast concrete elements of eco-revetment have complex and shaped structure,sealing, the pouring channel is narrow and depth, and is not conducive to thedischarge of bubbles and fill of concrete equably, forming the appearance defects onFront imitating stone-face, his back on bolt-hole, his back-1and his back-2ofconcentric digging-hole easily,which requires for workability and filling performanceis very high. Color difference of front imitating stone-face, size and number of theside bubbles and appearance defects, three sub-indexes and methods were evaluatedto establish a comprehensive appearance quality evaluation system about precastconcrete elements of ecological revetment.Proposed and designed a high-flowing SCC, and studied the fresh properties,effecting on mixing things extended degrees, T50, V-type funnel time, U-shapedinstrument Δh and gas content. That drawns: the amount of cement materials480kg/m3~510kg/m3, complex admixture of fly ash/slag=20%/5%or25%of singlefly ash, gravel graded B1:B2=4:6(B1of4.75~9.5mm, B2of9.5~16mm), sand rateof50%to53%, water consumption is185kg/m3~190kg/m3, when things will getbetter mixing state, its performance is ideal.The current concrete state can not meet filling properties of SCC, pouring process requires auxiliary vibrator. Proposing7kinds of fabrics and vibrationtechnology,it founds: the GY2, GY4, GY7improved appearance of concrete elementsof eco-revetment, in which individual indicators GY4products and productionstability would be better to optimize the enterprise actual production process.Moreover, the choice of water-soluble anti-foaming type release agents as well asmanual brushing can further enhance the appearance of the product quality.Based on significant economic and productivity considerations, Studied itsapplication of free vibration pouring of SCC. Under the existing conditions ofproduction: admixtures should be adjusted to the amount of25%fly ash alone, theamount of water and add0.5%latex powder to admixture,free vibrators and pouringprocess requires the expansion degree of SCC as much as possible, more than650mm,V-funnel time <10s, U-type instrument Δh <20mm, Which can be achieved freevibrated and pouring technology.