摘要
为提高硫氧镁水泥(MOSC)的耐水性,以煅烧沸石粉为掺合料制备MOSC,研究了煅烧前后沸石粉对MOSC凝结时间、力学性能、耐水性、相组成、微观形貌和孔结构的影响.结果表明:掺入煅烧沸石粉提高了MOSC的力学性能,且煅烧前后的沸石粉均可在MOSC体系中反应形成水化硅酸镁(M‑S‑H)凝胶,降低了MOSC的总孔隙率,提高了MOSC的耐水性,但掺入煅烧沸石粉的MOSC耐水性更优;MOSC中掺入20%经200 ℃煅烧、升温速率15 ℃/min处理的沸石粉后,MOSC的耐水性最优,其28 d抗压和抗折强度保留系数分别可达0.91、0.95.
硫氧镁水泥(MOSC)是由轻烧氧化镁粉与一定浓度MgSO4溶液混合而成的镁质胶凝材
沸石粉(ZE)经过煅烧后具有一定的活性,可与水泥浆体中的Ca(OH)2反应生成水化硅酸钙(C‑S‑H)凝胶,从而改善水泥的力学性
轻烧氧化镁粉(LBM)来自辽宁镁菱有限公司,其粒径累积分布10%的颗粒粒径D10、50%的颗粒粒径D50、90%的颗粒粒径D90分别为3.49、20.98、56.89 μm,活性氧化镁(α‑MgO)含量(质量分数,文中涉及的含量、组成等除特殊说明外均为质量分数)为65.5
Material | MgO | SiO2 | CaO | Fe2O3 | Al2O3 | Other |
---|---|---|---|---|---|---|
LBM | 86.50 | 2.32 | 2.34 | 1.47 | 1.42 | 5.95 |
ZE | 1.21 | 75.35 | 3.68 | 1.68 | 13.92 | 4.16 |

图1 LBM和ZE的激光粒度分布曲线
Fig.1 Laser particle size distribution of LBM and ZE
为了得到力学性能较好的MOSC,其原料摩尔比通常为:n(α‑MgO)/n(MgSO4)=6~10;n(H2O)/n(MgSO4)=18~2
根据GB/T 51003—2014《矿物掺合料应用技术规范》检测煅烧前后ZE的反应活性指数;利用S8 Tiger型X荧光分析仪检测LBM和ZE的化学组成;利用Mastersizer 2000型激光粒度分析仪检测LBM和ZE的细度;利用物理吸附仪检测ZE热处理前后多点比表面积的变化.按照GB/T 1346—2011《水泥标准稠度用水量、凝结时间、安定性检验方法》,使用维卡仪检测MOSC的初、终凝时间;按照GB/T 8077—2012《混凝土外加剂匀质性试验方法》测定MOSC的流动度(扩展直径);按照GB/T 17671—2021《水泥胶砂强度检验方法》,使用YDE‑300D型和YES‑2000型万能试验机测试MOSC的抗压强度和抗折强度;按照JC/T 313—2009《膨胀水泥膨胀率试验方法》,使用比长仪检测MOSC浸水前后的体积稳定性.
利用X’Pert powder 型X射线扫描仪(XRD)检测MOSC的相组成,并用Topas 6.0软件根据Rietveld分析方法测定MOSC的矿物相含量;利用Vertex 80v型傅里叶红外光谱仪(FTIR)测试MOSC的水化产物;利用ΣIGMA HD型扫描电子显微镜(SEM)观察喷金后MOSC试样断口处的微观形貌;采用SEM‑X射线微区分析(EDS)测试矿物相表面的元素组成;利用Pore Master 33型压汞仪(MIP)检测MOSC的总孔隙率和孔径分布.
待MOSC空气养护至28 d(浸水前)后,将其置于自来水中浸泡28 d(浸水后),测试其浸水前后的抗压强度和抗折强度.MOSC的抗压强度保留系数Rcs和抗折强度保留系数Rfs分别为:
(1) |
(2) |
式中:Rc0、Rf0分别为浸水前试样的抗压强度和抗折强度;Rc28、Rf28分别为浸水后试样的抗压强度和抗折强度.
煅烧前后ZE的微观形貌见

图2 煅烧前后ZE的微观形貌
Fig.2 Microstructure of ZE before and after calcination
煅烧前后ZE的比表面积、活性指数和晶粒尺寸见
Sample | Specific surface area/( | Activity index/% | Crystal size/nm |
---|---|---|---|
Z‑0 | 820.446 5 | 28.59 | 36.378 8 |
Z‑200‑5 | 849.403 2 | 27.58 | 37.375 2 |
Z‑200‑10 | 851.074 2 | 27.85 | 33.639 8 |
Z‑200‑15 | 854.426 2 | 29.25 | 30.973 1 |
Z‑400‑5 | 843.731 1 | 27.49 | 39.517 7 |
Z‑400‑10 | 846.486 6 | 27.74 | 36.115 1 |
Z‑400‑15 | 852.732 2 | 27.96 | 32.784 8 |
MOSC的凝结时间和流动度见

图3 MOSC的凝结时间和流动度
Fig.3 Setting time and fluidity of MOSC
MOSC的抗压强度和抗折强度见

图4 MOSC的抗压强度和抗折强度
Fig.4 Compressive strength and flexural strength of MOSC
浸水前后的MOSC抗压强度、抗折强度及保留系数见

图5 浸水前后MOSC的抗压强度、抗折强度及保留系数
Fig.5 Compressive strength, flexural strength and retention factor of MOSC before and after soaking in water
浸水前后MOSC的膨胀率见

图6 浸水前后MOSC的膨胀率
Fig.6 Expansion ratio of MOSC before and after soaking in water
MOSC的FTIR光谱见

图7 MOSC的FTIR光谱
Fig.7 FTIR spectra of MOSC
浸水前后MOSC的XRD图谱、矿物相含量和水化产物的晶粒尺寸见

图8 浸水前后MOSC的XRD图谱、矿物相含量和水化产物的晶粒尺寸
Fig.8 XRD pattern, proportion of mineral phases and grain size of hydration product of MOSC before and after soaking in water
MOSC的微观形貌见

图9 MOSC的微观形貌
Fig.9 Microstructures of MOSC
试样T‑200‑15的SEM‑EDS分析见

图10 试样T‑200‑15的SEM‑EDS分析
Fig.10 SEM‑EDS analysis of sample T‑200‑15
MOSC的SEM‑EDS分析见

图11 MOSC的SEM‑EDS分析
Fig.11 SEM‑EDS analysis of MOSC
MOSC的孔结构见
Sample | Total intrusion volume/(mL· | Total porosity(by volume)/% | Pore size distribution/% | ||
---|---|---|---|---|---|
d≤10 nm | 10 nm<d<100 nm | d≥100 nm | |||
Control | 0.112 5 | 12.04 | 20.65 | 75.49 | 3.86 |
UMOS | 0.134 1 | 11.22 | 23.81 | 73.73 | 2.46 |
T‑200‑15 | 0.107 4 | 10.66 | 24.48 | 72.47 | 3.05 |
T‑400‑15 | 0.114 1 | 13.47 | 22.76 | 74.13 | 3.11 |
(1)当升温速率固定时,掺入煅烧后沸石粉的MOSC的初、终凝时间均随着煅烧温度的提高而延长;当煅烧温度固定时,掺入煅烧后沸石粉的MOSC的初、终凝时间均随着升温速率的提高而缩短.
(2)煅烧后的沸石粉促进了MOSC体系中517相的生长,抑制了Mg(OH)2的形成,从而提高了MOSC的力学性能.掺入煅烧温度200 ℃,升温速率15 ℃/min沸石粉的MOSC 28 d抗压和抗折强度最高,较未掺沸石粉的MOSC分别提高了23.16%、58.67%.
(3)未煅烧的沸石粉在MOSC体系中反应形成水化硅酸镁凝胶,该凝胶可填充MOSC基体内部的孔隙,从而提高MOSC的力学性能和耐水性.而煅烧后的沸石粉具有更高的化学反应活性,这使得沸石粉中的活性SiO2更容易与MOSC体系中的Mg(OH)2反应形成水化硅酸镁凝胶.同时,煅烧后的沸石粉可降低体系中Mg(OH)2的含量及抑制Mg(OH)2的生长,从而进一步提高MOSC的耐水性.其中,掺入煅烧温度200 ℃,升温速率15 ℃/min沸石粉的MOSC浸水28 d后的抗压和抗折强度保留系数最高,分别为0.91和0.95.
参考文献
WALLING S A, PROVIS J L. Magnesium‑based cements: A journey of 150 years, and cements for the future? [J]. Chemical Reviews, 2016, 116(7):4170‑4204. [百度学术]
JIANG Y Z, WANG C Y, XU Z S, et al. Surface modification mechanism of magnesium oxysulfate whiskers via wet chemical method[J]. Rare Metals, 2015, 35(11):874‑880. [百度学术]
WU C Y, YU H F, ZHANG H F, et al. Effects of phosphoric acid and phosphates on magnesium oxysulfate cement[J]. Material and Structures, 2015, 48(4):907‑917. [百度学术]
BA M F, XUE T, HE Z M, et al. Carbonation of magnesium oxysulfate cement and its influence on mechanical performance[J]. Construction and Building Materials, 2019, 223:1030‑1037. [百度学术]
柳俊哲, 孙武, 巴明芳, 等. 碳化对水泥石中硫元素分布的影响[J]. 建筑材料学报, 2015, 18(3):477‑481. [百度学术]
LIU Junzhe, SUN Wu, BA Mingfang, et al. Effect of carbonization on the distribution of sulfur in cement stone[J]. Journal of Building Materials, 2015, 18(3):477‑481. (in Chinese) [百度学术]
CHEN X Y, ZHANG T T, CHEESEMAN C R, et al. Production of rapid‑hardening magnesium oxysulfate (MOS) cement containing boric acid[J]. Journal of Materials of Civil Engineering, 2022, 34(5):04022045. [百度学术]
靳凯戎, 许星星, 陈啸洋, 等. 花岗岩石粉对硫氧镁水泥耐水性能的影响[J]. 建筑材料学报, 2022, 25(8):767‑772, 780. [百度学术]
JIN Kairong, XU Xingxing, CHEN Xiaoyang, et al. Effect of granite powder on water resistance of magnesium oxysulfate cement[J]. Journal of Building Materials, 2022, 25(8):767‑772, 780. (in Chinese) [百度学术]
朱杰兆, 薛涛, 巴明芳. 高抗折硫氧镁基无机复合胶凝材料的制备及其机理[J]. 宁波大学学报(理工版), 2017, 30(6):66‑72. [百度学术]
ZHU Jiezhao, XUE Tao, BA Mingfang. Preparation and mechanism of high refractive magnesium sulfoxide‑based inorganic composite cementitious material[J]. Journal of Ningbo University (Science and Technology), 2017, 30(6):66‑72. (in Chinese) [百度学术]
LIU T, LI C Q, LI L, et al. Effect of fly ash and metakaolin on properties and microstructure of magnesium oxysulfate cement[J]. Materials, 2022, 15(4):1334‑1348. [百度学术]
ZHOU J Q, WU C Y. Effects of nano‑silica and silica fume on properties of magnesium oxysulfate cement[J]. Journal of the Ceramic Society of Japan, 2020, 128(3):164‑173. [百度学术]
刘业金. 沸石粉和玻璃粉复合对混凝土性能的影响[J]. 非金属矿, 2021, 44(1):43‑46. [百度学术]
LIU Yejin. Effects of zeolite powder and glass powder on the properties of concrete[J]. Non‑metallic Mines, 2021, 44(1):43‑46. (in Chinese) [百度学术]
陈啸洋, 张婷婷, 常钧, 等. 硅酸对硫氧镁水泥耐水性能的影响[J]. 硅酸盐学报, 2023, 51(8):2017‑2026. [百度学术]
CHEN Xiaoyang, ZHANG Tingting, CHANG Jun, et al. Effect of silicic acid on water resistance of magnesium sulfate cement[J]. Journal of the Chinese Ceramic Society, 2023, 51(8):2017‑2026. (in Chinese) [百度学术]
许星星, 李晶, 陈啸洋, 等. 蔗糖和活性氧化镁对硫氧镁水泥水化进程的影响[J]. 建筑材料学报, 2023, 26(2):193‑199. [百度学术]
XU Xingxing, LI Jing, CHEN Xiaoyang, et al. Effects of sucrose and activated magnesium oxide on the hydration process of magnesium oxysulfate cement[J]. Journal of Building Materials, 2023, 26(2):193‑199. (in Chinese) [百度学术]
TANG S W, YUAN J H, CAI R J, et al. In situ monitoring of hydration of magnesium oxysulfate cement paste:Effect of MgO/MgSO4 ratio[J]. Construction and Building Materials, 2020, 251:119003. [百度学术]
巴明芳,朱杰兆,薛涛, 等.原料摩尔比对硫氧镁胶凝材料性能的影响[J]. 建筑材料学报, 2018, 21(1):124‑130. [百度学术]
BA Mingfang, ZHU Jiezhao, XUE Tao, et al. Influence of molar ratio on properties of magnesium oxysulfate cementitious materials[J]. Journal of Building Materials, 2018, 21(1):124‑130.(in Chinese) [百度学术]
MERTENS G, SNELLINGS R, VANBALEN K, et al. Pozzolanic reactions of common natural zeolites with lime and parameters affecting their reactivity[J]. Cement and Concrete Research, 2009, 39(3):233‑240 [百度学术]
汪衢, 白丽梅, 马玉新, 等. 菱镁矿煅烧制备氧化镁及其活性检测的研究进展[J]. 有色金属(冶炼部分), 2022, 9(1):36‑44. [百度学术]
WANG Qu, BAI Limei, MA Yuxin, et al. Research progress on preparation of magnesium oxide by calcination of spinel and its activity detection[J]. Nonferrous Metals(Extractive Metallurgy), 2022, 9(1):36‑44. (in Chinese) [百度学术]
MALTELE C, PISTOLESI C, LOLLI A, et al. Combined effect of expansive and shrinkage reducing admixtures to obtain stable and durable mortars[J]. Cement and Concrete Research, 2004, 35(12):2244‑2251. [百度学术]
BERNARD E, LOTHENBACH B, GOFF F L, et al. Effect of magnesium on calcium silicate hydrate (CSH)[J]. Cement Concrete Research, 2017, 97:61‑72. [百度学术]
SIMONSEN M, SONDERBY C, LI Z, et al. XPS and FTIR investigation of silicate polymers[J]. Journal of Materials Science, 2009, 44 (8):2079‑2088. [百度学术]
DAUZERES A, ACHIEDO G, NIED D, et al. Magnesium perturbation in low‑pH concretes placed in clayey environment‑solid characterizations and modeling[J]. Cement and Concrete Research, 2016, 79:137‑150. [百度学术]