Influence of limestone content, gypsum content and fineness on early age properties of Portland limestone cement produced by inter-grinding
Influence of limestone content, gypsum content and fineness on early age properties of Portland limestone cement produced by inter-grinding
复制标题
DOI：
10.1016/j.cemconcomp.2010.10.001
复制
发表时间：
2011-02
影响因子：
10.5
通讯作者：
E. Irassar;D. Violini;V. Rahhal;C. Milanesi;M. Trezza;V. Bonavetti
中科院分区：
文献类型：
--
作者：
E. Irassar;D. Violini;V. Rahhal;C. Milanesi;M. Trezza;V. Bonavetti
本文研究了在全尺寸水泥厂中由熟料、石膏和石灰石相互研磨制成的波特兰石灰石水泥（PLC）的性能，同时改变石灰石填料的含量（LF - 0%和24%）、石膏的含量（GC - 2.5%和5.0%）和PLC的细度，以45μm筛子（R45 - 5%和18%）上保留的分数来衡量。采用23个试验设计，研究了这些变量的共同作用对混合水泥粒径分布（PSD）和早期龄期性能的影响。用松香- rammler - springer - bennett （RRSB）分布函数参数评价细度表明，均匀性指数（n-参数）与LF含量有很大关系；而特征直径（x′参数）取决于R45和LF含量。对于间磨过程，加入LF减少了需水量，减少R45增加了需水量，产生了一种补偿。凝结时间主要受R45的影响；LF会产生少量的改性，石膏含量和石膏-石灰石相互作用的影响不明显。量热研究表明，LF降低了主峰高度和总放热，而石膏含量改变了加速时间和峰后水化，特别是对细水泥。随着R45、LF含量和石膏含量的增加，化学收缩率减小。直到2天，强度主要由PLC中的R45和LF控制，它们的作用相反。在早期龄期，石膏含量对早期性能的影响增加至48h。XRD分析表明，其对硅酸钙水化作用的促进作用在前1h，对钙矾石形成的促进作用在24h后。
This paper examines the behavior of Portland limestone cements (PLCs) made by inter-grinding clinker, gypsum and limestone in a full size-cement plant, while varying the content of limestone filler (LF – 0% and 24%), content of gypsum (GC – 2.5% and 5.0%) and PLC fineness, measured as that fraction retained on a 45μm sieve (R45 – 5% and 18%). The influence of the combined action of these variables on the particle size distribution (PSD) and early age properties of blended cement was studied using a 23experimental design. Fineness evaluated by the parameters of the Rosin–Rammler–Springer–Bennett (RRSB) distribution function shows that the uniformity index (n-parameter) depends strongly on LF content; while the characteristic diameter (x′-parameter) depends on R45 and LF content. As for the inter-grinding process, water demand is reduced by incorporation of LF and increased by reduction of R45, producing a compensation. Setting time is mainly affected by R45; LF produces a few modifications and the influence of gypsum content and gypsum–limestone interaction are not as obvious. Calorimetry studies show that LF decreases the height of the main peak and the total heat released, while gypsum content modifies the time of acceleration and the post-peak hydration, specifically for fine cements. In accordance, chemical shrinkage decreases when R45, LF content and gypsum content increase. Up to 2 days, strength is mainly governed by the R45 and the LF in PLC, which act inversely. At early ages, the influence of gypsum content on early properties increases up to 48h. XRD analysis shows its stimulation of calcium silicate hydration during the first hours and ettringite formation after 24h.