矿粉/偏高岭土对天然水硬性石灰早期性能的影响

Effects of slag powder/metakaolin on the early performance of natural hydraulic lime

天然水硬性石灰(NHL)在古建筑修缮工程中的应用效果是水泥和传统气硬性石灰所无法比拟的,但早期性能发展偏慢的特性使其应用受限。本文研究了矿粉/偏高岭土改性NHL早期硬化过程中物理力学性能、水化放热特性、物相组成和转变以及微观结构演变过程,系统地评估了矿粉/偏高岭土对NHL基材料早期性能发展的影响。结果表明:矿粉可以改善NHL基砂浆的流动性;矿粉/偏高岭土通过火山灰反应生成水化铝酸钙(C_(3)AH_(6))、水化碳铝酸钙(C_(4)AĈH_(11))以及水化硅酸钙(C—S—H),可促进NHL基材料凝结硬化、显著提高其抗压及抗折强度。本研究为推动火山灰质材料复合NHL在古建筑修复工程中的应用提供参考。

Natural Hydraulic Lime(NHL)has exceptional application in restoring ancient buildings compared to Portland cement and conventional air-hardening lime,but the characteristic of slow early performance development limits its fields of application.This paper studied the physical and mechanical properties,hydration exothermic properties,phase composition and transformation,and microstructure evolution of slag powder/metakaolin composite NHL during the early hardening process.The influence of slag powder/metakaolin on the hardening process and performance development of NHL are systematically evaluated.Results show that slag powder can improve the fluidity of NHL-based mortar;slag powder/metakaolin generates calcium aluminate hydrate(C_(3)AH_(6)),calcium carboaluminate hydrate(C_(4)AĈH_(11))and calcium silicate hydrate(C-S-H)through pozzolanic reaction to promote the setting and hardening of NHL-based materials and significantly improve their compressive and flexural strength.This study provides reference for promoting the application of pozzolanic material composite NHL in the resto-ration of ancient buildings.