生石灰/焙烧改性电解锰渣对水泥混凝土性能的影响

Influence of Quicklime/Calcined Modified Electrolytic Manganese Slag on the Performance of Cement Concrete

改性处理是提高电解锰渣(Electrolytic manganese residue,简称EMR)胶凝活性的有效方法。采用添加改性剂(生石灰)和焙烧两种方法对电解锰渣进行改性预处理,研究了添加不同电解锰渣掺合量和不同焙烧温度下电解锰渣对混凝土力学性能的影响规律。研究结果表明:掺合量为3%~10%的改性电解锰渣和300~500℃焙烧电解锰渣制备的混凝土在龄期28 d时分别获得40.1~43.5 MPa和36.6~42.7 MPa的抗压强度;当改性电解锰渣掺合量为10%时,掺合生石灰改性和450℃焙烧条件下电解锰渣的混凝土抗压强度较未掺合电解锰渣混凝土试块抗压强度分别提高了2 MPa和5 MPa;经生石灰改性和450℃条件下焙烧1 h,电解锰渣中CaSO_(4)·0.5H_(2)O全部转化为CaSO_(4)·2H_(2)O和硬石膏;掺合生石灰改性和450℃焙烧条件下电解锰渣制备的混凝土生成了更多的C-S-H凝胶和AFt,混凝土力学性能增强。表明CaSO_(4)·2H_(2)O和硬石膏能够促进水化作用,可提高混凝土早期的抗压强度和抗折强度。

Modification is an effective method to improve the cementitious activity of electrolytic manganese residue(EMR).The electrolytic manganese slag was modified by adding modifier(lime)or roasting method.The effects of different electrolytic manganese slag content and different roasting temperature on the mechanical properties of concrete were studied.The results showed that the compressive strength of the concrete prepared by the modified electrolytic manganese slag with the blending amount of 3%~10%and the electrolytic manganese slag calcined at 300~500℃were 40.1~43.5 MPa and 36.6~42.7 MPa respectively at the age of 28 d.When the content of modified electrolytic manganese slag was 10%,the compressive strength of concrete with electrolytic manganese slag modified by mixed quicklime and roasted at 450℃were 2 MPa and 5 MPa respectively,higher than that of concrete without electrolytic manganese slag.Under the condition of lime modification or calcination at 450℃for 1 h,CaSO_(4)·0.5H_(2)O in electrolytic manganese slag was completely converted into CaSO_(4)·2H_(2)O and anhydrite,more C-S-H gel and AFt were generated in the prepared concrete and the mechanical properties of concrete were enhanced.It showed that CaSO_(4)·2H_(2)O and anhydrite could promote hydration and improve the early compressive strength and flexural strength of concrete.