CAJ | 학술논문

研究了早龄期冻结压力等荷载、负温及早龄期荷载和负温耦合作用对冻结竖井井壁C60混凝土抗压强度、氯离子扩散系数和声发射特征的影响，并通过扫描电镜分析其内部微裂缝。结果表明：早龄期荷载加载时间越早对混凝土28 d抗压强度的影响越大，当外部荷载作用时间在3 d以后且荷载水平在混凝土当天强度40%以内时，混凝土28 d强度几乎不受影响；冻结井井帮负温环境会延缓井壁混凝土早期水化，防冻剂的加入利于加快混凝土水化和强度的发展；在早龄期荷载及负温耦合作用下，混凝土28 d抗压强度降低明显，氯离子扩散系数大大增加，混凝土的渗透性由“中冶变为“高冶，内部产生了缺陷和微裂缝导致声发射“活跃阶段冶提前，且混凝土呈现明显的塑性变形。
연구료조령기동결압력등하재、부온급조령기하재화부온우합작용대동결수정정벽C60혼응토항압강도、록리자확산계수화성발사특정적영향，병통과소묘전경분석기내부미렬봉。결과표명：조령기하재가재시간월조대혼응토28 d항압강도적영향월대，당외부하재작용시간재3 d이후차하재수평재혼응토당천강도40%이내시，혼응토28 d강도궤호불수영향；동결정정방부온배경회연완정벽혼응토조기수화，방동제적가입리우가쾌혼응토수화화강도적발전；재조령기하재급부온우합작용하，혼응토28 d항압강도강저명현，록리자확산계수대대증가，혼응토적삼투성유“중야변위“고야，내부산생료결함화미렬봉도치성발사“활약계단야제전，차혼응토정현명현적소성변형。
The effects of early-age frozen pressure, negative temperature, and early-age load and negative temperature coupling on the strength, chloride diffusion and acoustic emission characteristic of freezing shaft wall C60 concrete were studied, and the internal microcracks were analyzed by scanning electron microscopy ( SEM) . It is found that the earlier the early-age load applies, the greater effect it has on the 28 d compressive strength of the concrete. But when the external load is applied 3 d later and the load level is less than 40% of the day's strength, the 28 d compressive strength of the concrete is almost not affected. A negative temperature environ-ment of the freezing shaft wall can delay early concrete hydration, and antifreeze speeds up the development of concrete hydration and strength. Under the early-age load and negative temperature coupling effect, the 28 d compressive strength and durability of the concrete decrease, the chloride diffusion coefficient increases apparently, the concrete permeability changes from middle to high, the internal microcracks and deficiencies lead to advancing the active phase of acoustic emission, and the concrete presents apparent plastic deform-ation.