煅烧温度对天然水硬石灰物理力学特性影响研究

Effect of Calcination Temperature on Physical and Mechanical Properties of Natural Hydraulic Lime

研究了900~1150℃煅烧温度对寒武纪灰岩制备的天然水硬石灰物理力学特性的影响。利用XRD谱、SEM照片和消化速率表征煅烧产物特性,风吹成粉后检测天然水硬石灰凝结时间和抗折抗压强度。研究表明900~1150℃煅烧温度范围内,煅烧产物主要成分均为游离CaO和β-Ca_(2)SiO_(4),28 d抗压强度均达到天然水硬石灰NHL2的要求。煅烧产物游离CaO含量和消化速率随煅烧温度升高先增大后减小,其中950℃时达到峰值。天然水硬石灰凝结时间随煅烧温度升高逐渐缩短,但950℃时较1000℃时有明显减少,抗折、抗压强度随煅烧温度变化无明显规律,1150℃时28 d强度最高。

Effect of calcination temperature from 900℃to 1150℃on the physical and mechanical properties of natural hydraulic lime prepared from cambrian limestone was investigated.The calcined products were characterized by X-ray diffractometer,scanning electron microscopy and slaking reactivity,and the wind slaked lime was characterized by setting time,flexural strength and compressive strength.The test results show that free-CaO andβ-Ca_(2)SiO_(4) are detected and the compressive strength values at 28 d allows for the classification of the natural hydraulic lime as NHL2 for all calcination temperatures from 900℃to 1150℃.The free-CaO content and slaking reactivity of the calcined products first increase and then decrease with the increase of calcination temperature,and reach the peak values where the calcination temperature is 950℃.The setting time of natural hydraulic lime gradually decreases with the increase of calcination temperature,and the exception is at 950℃where the setting time is lower than at 1000℃.The mechanical properties of natural hydraulic lime does not demonstrate a clear relation to the calcination temperature,and the lime binder calcined at 1150℃reaches the highest flexural and compressive strengths at 28 d.