(1. 北京科技大學(xué) 土木與資源工程學(xué)院，北京 100083；
2. 北京科技大學(xué) 金屬礦山高效開(kāi)采與安全教育部重點(diǎn)實(shí)驗(yàn)室，北京 100083；
3. 金川集團(tuán)股份有限公司 鎳鈷資源綜合利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，金昌 737100)
摘 要: 攪拌時(shí)間是保證膏體拌合物均勻的最快捷且經(jīng)濟(jì)的方法。本文以金川礦區(qū)粗骨料及全尾砂為主要研究對(duì)象，采用全面實(shí)驗(yàn)的方法研究了膏體質(zhì)量濃度和攪拌時(shí)間對(duì)膏體表面狀態(tài)、流動(dòng)性及硬化早期強(qiáng)度的影響，并結(jié)合SEM掃描對(duì)不同攪拌時(shí)間條件下膏體硬化強(qiáng)度的發(fā)生機(jī)制進(jìn)行探討。結(jié)果表明：對(duì)應(yīng)于攪拌軸不同位置的膏體振動(dòng)擴(kuò)散度并未呈現(xiàn)明顯的規(guī)律性，工業(yè)攪拌機(jī)攪拌軸不同位置對(duì)膏體均質(zhì)性的影響不大。隨著攪拌時(shí)間增加，膏體振動(dòng)擴(kuò)散度越來(lái)越大，流動(dòng)性逐漸得到改善。質(zhì)量濃度較大時(shí)會(huì)影響膏體物料混合的均質(zhì)性，對(duì)于試驗(yàn)中質(zhì)量濃度為78%的充填物料，經(jīng)過(guò)6 min的攪拌尚不足以得到密實(shí)均勻的高質(zhì)量漿體。攪拌作用可以促進(jìn)膏體內(nèi)部結(jié)構(gòu)的形成，充分的攪拌時(shí)間可以提高水泥在膏體中的分散性，C-S-H凝膠產(chǎn)量增大，提高膏體的硬化早期強(qiáng)度，結(jié)合膏體制備工藝，建議攪拌時(shí)間控制在4~5 min。
關(guān)鍵字: 攪拌時(shí)間；膏體均質(zhì)性；流動(dòng)性；早期強(qiáng)度；粗骨料
（1. School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Key Laboratory of High-Efficient Mining and Safety of Metal Mines, Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China;
3. National Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization, Jinchuan Group Co., Ltd., Jinchang 737100, China）
Abstract:Mixing time is the quickest and the most economical way to ensure the homogeneity of paste mixes. In this paper, the effects of mass concentration and mixing time on the surface state, fluidity, and early hardened strength of the paste were investigated by a comprehensive experimental method using coarse aggregate and whole tailing sand from the Jinchuan mine as the main research objects. The mechanism of hardened strength of paste under different mixing time conditions was also investigated by SEM. The results show that the paste vibration diffusivity at different positions of the stirring shaft does not show obvious regularity, which has little significant effect on the homogeneity of the paste mixing at different positions of the industrial mixer. With the increase of mixing time, the vibration diffusion coefficient gradually increases, which indicates that the paste fluidity gradually improves. The mass concentration affects the homogeneity of the paste mix, and a mixing time of 6 min is not sufficient to convert a filler with a concentration of 78% into a dense and homogeneous quality paste. Mixing action can promote the formation of the internal structure of the paste, and sufficient stirring time can make the dispersion of cement in the paste increase and promote the C-S-H gel yield, thus improving the hardened strength of the paste. Combined with the paste preparation craft, the mixing time is recommended to be 4-5 min.
Key words: mixing time; homogeneity of paste; fluidity; early strength; coarse aggregate
