石灰石粉含量和粒径对水泥水化热的影响

为研究石灰石粉(以下简称石粉)参数对水泥水化热的影响,利用TAM Air-八通道微量热仪探究不同石粉含量和粒径对水泥水化放热量以及水化放热速率的影响。研究表明,随着石粉含量的增加,辅助胶凝材料的水化放热量和水化放热速率总体上呈降低的趋势。其中当石粉含量为15%(质量分数)时,石粉粒径为400目时放热量为223.22 J/g,水化峰值速率为2.399 2 mW/g,石粉粒径为3 000目时放热量为215.98 J/g,水化峰值速率为2.214 0 mW/g,其放热量和水化峰值速率降低的趋势最明显。同时,当石粉掺量较大时,石粉粒径对水化反应的影响更加明显,粒径过小或者过大都会提高水化放热量和水化放热速率。当石粉粒径为1 250目时水化放热量较小且水化放热速率较低。通过物相分析发现,石粉的加入不会使体系产生新物质,当石粉含量为15%(质量分数)、粒径为1 250目时,Ca(OH)₂衍射峰强度最高并伴随着大量C-S-H的生成,说明了该组石粉能够更大程度地促进水泥水化,使反应更充分。

Effects of Limestone Powder Content and Particle Size on Hydration Heat of Cement

In order to study the influences of limestone powder parameters on the hydration heat of cement, the effects of different content and particle size of limestone powder on the hydration heat and hydration heat rate of cement were analyzed by TAM Air-eight-channel microcalorimeter. The results show that with the increase of content of limestone powder, the hydration heat and hydration heat rate of auxiliary cementitious materials generally show a trend of decreasing. The hydration heat and hydration peak rate of 15% (mass fraction) limestone decrease the most, the hydration heat at 400 mesh is 223.22 J/g, the hydration peak rate is 2.399 2 mW/g, the hydration heat at 3 000 mesh is 215.98 J/g, and the hydration peak rate is 2.214 0 mW/g. Meanwhile, when the content of limestone powder is large, the influence of particle size on the hydration reaction is more obvious. Too small or too large particle size will increase the hydration heat and hydration heat rate. When the particle size of limestone powder is 1 250 mesh, the hydration heat is small and the hydration heat rate is low. Through phase analysis, it is found that the system with limestone powder do not produce new substances. When the content of limestone powder is 15% (mass fraction) and the particle size is 1 250 mesh, the diffraction peak intensity of Ca(OH)₂ is the highest and accompanied by the formation of a large amount of C-S-H, indicating that this group of limestone powder can greatly promote the hydration reaction of cement.