花岗岩机制砂细粉对聚羧酸减水剂吸附性能的影响

Effect of Microfines in Granite Manufactured Sand on Adsorption Characteristics of Polycarboxylate Superplasticizer

摘要:

测定了砂石联产制砂和制砂楼单独制砂2种干法制砂工艺生产的花岗岩机制砂中细粉的理化特性，研究了细粉含量对机制砂亚甲蓝值（MBV）和胶砂流动性的影响；通过测试总有机碳（TOC）和Zeta电位，分析了5种聚羧酸减水剂在联产机制砂细粉（CMF）和单产机制砂细粉（SMF）上的吸附性能. 结果表明：随着细粉含量的增加，机制砂的MBV增大，胶砂达到等流动性所需减水剂掺量提高，且性能较差的CMF的影响程度显著；CMF对5种聚羧酸减水剂的吸附性均很强，而SMF对减水剂的吸附率与水泥相差不大；CMF对于减水剂的高吸附性并非源于纯石粉，而是源于机制砂生产中混杂在细粉中的泥粉或岩石风化颗粒.

Abstract:

Physical and chemical properties of two microfines in the granite manufactured sands produced by two dry processes， namely the combination production of sand and gravel and the separate sand-manufacturing plant were tested. The effects of microfines content on methylene blue value （MBV） of manufactured sand and fluidity of mortar were studied. Total organic carbon （TOC） and Zeta potential were used to measure the adsorption properties of five polycarboxylate superplasticizers （PCE） on the two granite microfines of microfines contained in the manufactured sand from the combination production of sand and gravel process （CMF） and microfines contained in the manufactured sand from the separate sand-manufacturing plant process （SMF）. The results show that with the increase of granite microfines content， the MBV of manufactured sand increases， and the PCE demand dosage to achieve equal fluidity of mortar is increased， and the influence of the low-quality CMF is more significant than that of the SMF； The CMF can be very strongly adsorbed onto the five PCEs， and the adsorption rate of the SMF onto the PCEs is similar to that of the cement. The high adsorption of the CMF onto PCE does not result from the pure rock fines， but from the clay powder or weathered particles which are mixed in the microfines during the production of manufactured sand.