为研究酸性水化学环境对路用水泥基固化盾构渣土材料的侵蚀作用及机理，首先，采用一种新型早强型水泥基材料（ESCA）和普通硅酸盐水泥（P·O
42.5）2种固化剂对来自芜湖市城南过江隧道工程的盾构渣土进行固化，并进行室内固化试验；然后，配制4种pH值分别为7、5、3、1的水溶液对2种固化渣土试样进行45 d的浸泡，并对比测试试样的物理性质（质量和纵波波速）和力学性质（无侧限抗压强度）；最后，采用扫描电镜（scanning electron microscope，SEM）和工业CT（computed tomography）系统研究酸性侵蚀对固化渣土微观结构的损伤劣化机理。结果表明： 1）在经过45 d的酸浸试验后，ESCA型和P·O 42.5型固化渣土的承载结构均有不同程度的劣化，浸泡溶液pH=1时2种固化渣土的强度分别下降65.61%和72.25%； 2）浸泡溶液pH值的降低会使2种固化渣土试样的塑性变形增大，在pH=3时2种固化渣土试样均表现出由劈裂破坏向剪切破坏转变的趋势； 3）相比P·O 42.5型固化渣土，ESCA型固化渣土酸侵蚀后的孔隙发育较少，拥有更好的耐酸腐蚀能力。
In this study, the erosive
effects and mechanisms of acidic water-chemical
environments on road-use cement-based cured shield muck materials are investigated. First, indoor
curing experiments are carried out on shield muck produced from the Chengnan
river-crossing tunnel in Wuhu, China, using two curing
agents, a new type of early-strengthening cement-based material (ESCA) and ordinary Portland cement 42.5 (P·O 42.5). Then, four aqueous solutions with pH values of 7, 5, 3, and
1 are prepared to soak the two cured muck specimens for a period of 45 days,
and the specimens are comparatively tested for physical (mass and longitudinal
wave velocity) and mechanical properties (unconfined compressive strength).
Finally, scanning electron microscope and industrial computed tomography system
are used to investigate the damage and deterioration mechanism of acid erosion
on the microstructure of cured muck. The results show that: (1) The bearing
structures of both ESCA-type and P·O 42.5-type cured specimens are deteriorated
to different degrees after 45 days of acid leaching tests, and the strength of
the two cured specimens decreases by 65.61% and 72.25% at pH=1 of the leaching
solution, respectively. (2) The decrease of the pH value of the soaking
solution increases the plastic deformation characteristics of the two types of
cured muck specimens, and both types of cured muck specimens show a tendency to
change from cleavage damage to shear damage at pH=3. (3) Compared with the P·O 42.5-type of cured muck specimens, the ESCA-type of cured muck specimens has less pore development after acid
attack, and possesses a better ability to withstand acid corrosion.
