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研究了掺入热闷钢渣微粉对铁路轨枕混凝土力学性能、自收缩和水化产物的影响。结果表明:钢渣微粉的掺入对抑制铁路轨枕混凝土的自收缩具有明显的效果。当钢渣微粉掺量为胶凝材料20%时,所制备的轨枕混凝土28 d自收缩值仅为未掺加钢渣混凝土的38.79%。XRD、FT-IR和FE-SEM分析表明:热闷钢渣中所含的少量较惰性的死烧游离氧化钙(f-CaO)和游离氧化镁(f-MgO)的水化膨胀,是抑制轨枕混凝土自收缩的主要膨胀源。经超细粉磨的钢渣掺入混凝土后,f-CaO和f-MgO相在混凝土中高度分散,其水化膨胀对混凝土强度无破坏作用;在混凝土硬化的中后期,体系中钙矾石(AFt)和C-S-H凝胶的协同生长,抑制了轨枕混凝土的自收缩并提高了力学性能。
The effects of the incorporation of hot slag powder on the mechanical properties, self-shrinkage and hydration products of railway sleeper concrete were studied. The results show that the incorporation of slag powder has a significant effect on inhibiting the self-shrinkage of railway sleeper concrete. When the content of slag powder is 20% of cementitious material, the self-shrinkage value of sleeper concrete prepared for 28 days is only 38.79% of that of unadulterated steel slag concrete. The results of XRD, FT-IR and FE-SEM show that the hydration expansion of a small amount of relatively inert calcined free calcium oxide (f-CaO) and free magnesium oxide (f-MgO) The main source of self-shrinking of concrete. The ultrafine grinding steel slag mixed with concrete, f-CaO and f-MgO phase highly dispersed in the concrete, the hydration expansion of concrete strength without damaging role in the concrete hardening in the late, the system ettringite ( AFt) and CSH gel inhibited the self-shrinkage of sleeper concrete and improved the mechanical properties.