岩土质文物加固材料烧料礓石超细粉的表征及其固化机理研究

Characterization and curing mechanism of calcined ginger nuts ultrafine powder as a reinforcement material for rock and earth cultural relics

以烧料礓石为原料,在1000℃焙烧3 h,通过气流涡旋磨机粉磨、微粉分级选粉,最后用单筒分离器分离后得到烧料礓石超细粉.粒径分布特征及比表面积分析结果表明,超细粉的粒径尺寸为0.2~150μm,且优势粒径尺寸主要分布在0.5μm和30μm;比表面积为2.81 m^(2)·g^(-1),是普通烧料礓石比表面积的1.21倍,达到超细粉末的要求.以烧料礓石超细粉和其不同养护龄期浆体为研究对象,通过FT-IR,XRD,TG/DTG,SEM,EDS和XPS进行结构、组成、热稳定性和形貌分析,进而讨论超细烧料礓石的固化机理.结果表明,烧料礓石超细化后的主要产物为CaO,Ca(OH)_(2),CaCO_(3),SiO_(2)和β-CaSiO_(3);其浆体在养护28 d和90 d后产生β-CaSiO_(3)·n H_(2)O和Ca_(2)Al_(2)SiO_(7)·n H_(2)O等新物质,同时CaCO_(3),Ca(OH)_(2)和SiO_(2)仍然存在;烧料礓石超细后浆体早期强度形成主要为水化反应,后期强度持续增长以水化反应和气化反应为主,性能具有“水硬”和“气硬”双重特性,化学组成及固化机理具有类似欧洲“天然水硬性石灰”的性质,达到欧洲“水硬石灰”的标准.因此,烧料礓石超细粉在岩土质文物加固保护中具有广阔的应用前景.

In this paper,calcined ginger nuts was calcined at 1000℃for 3 h,and then the ultrafine powder of calcined ginger nuts was obtained by air vortex mill grinding,classifier and separation technology.The particle size distribution and specific surface area analysis showed that the particle size of ultrafine powder is ranged from 0.2 to 150μm,and the particle size is mainly distributed in 0.5μm and 30μm.The specific surface area is 2.81 m^(2)·g^(-1),which is 1.21 times of ordinary calcined ginger nuts and meets the requirements of ultrafine powder.The structure,composition,thermal stability and morphology of calcined ginger nuts ultrafine powder and its pastes at different curing ages were analyzed by FT-IR,XRD,TG/DTG,SEM,EDS and XPS,and the curing mechanism of calcined ginger nuts ultrafine powder was discussed.The results showed that the main products of the calcined ginger nuts ultrafine powder are CaO,Ca(OH)_(2),CaCO_(3),SiO_(2)andβ-CaSiO_(3).The pastes produce CaSiO_(3)·n H_(2)O and Ca_(2)Al_(2)SiO_(7)·n H_(2)O after curing for 28 d and 90 d,while CaCO_(3),Ca(OH)_(2)and SiO_(2)are still present.After ultrafining,the early strength of pastes for the alcined ginger nuts is mainly formed by hydration reaction,and the late strength continues to increase by hydration reaction and carbonation reaction.The performance of calcined ginger nuts ultrafine powder has the dual characteristics of“water-hardening”and“air-hardening”.The chemical composition and curing mechanism of ultrafine powder are similar to that of European“water-hardening lime”,and meet the European“water-hardening lime”standard.Therefore,the calcined ginger nuts ultrafine powder has a broad application prospect in the reinforcement and protection of rock and soil cultural relics.