干湿循环对固化污泥微观结构及强度的影响

Effects of dry-wet cycles on microstructure and strength of solidified sludge

为探索用作填埋场覆盖材料的固化污泥的干湿循环耐久性,开展了干湿循环条件下碱渣矿渣石灰固化污泥强度性质试验。结果表明:随着干湿循环次数的增加,水化反应持续进行,钙矾石、水铝钙石和水化硅酸钙等水化产物增多,试样孔隙体积减小,结构趋于密实;总体来看,固化污泥的无侧限抗压强度随着干湿循环次数的增加呈增大趋势,7次干湿循环后试样的强度为干湿循环前的1.16~1.45倍;从微观结构和无侧限抗压强度来看,碱渣矿渣石灰固化污泥具有良好的干湿耐久性。

To explore the dry-wet durability of solidified sludge in the application of landfill cover,solidification strength tests of soda residue-slag-lime were performed under the condition of dry-wet cycles.The results show that the hydration reaction continues with the increase of dry-wet cycles,leading to increasing amount of hydration products including ettringite,hydro aluminite and calcium silicate hydrate,decreasing pore volume,and dense microstructure.In general,the unconfined compressive strength has an increase trend with the dry-wet cycles.The strength after the seventh dry-wet cycle is 1.16 to 1.45 times of that before the cycles.From the perspective of microstructure and unconfined compressive strength,sludge solidified with soda residue-slag-lime has good durability under dry-wet cycles.