MgO活性对新型水化硅酸镁水泥性能的影响

摘要/Abstract

摘要： 通过对原料轻烧氧化镁粉在不同温度下进行二次恒温煅烧1.5 h制备不同活性MgO,研究了不同活性MgO与硅灰(SF)和磷酸氢二钾(K₂HPO₄)所制备的新型水化硅酸镁水泥胶凝材料(又称水化磷硅酸镁水泥,MSPHC)的凝结时间、流动度、抗压强度、反应溶液pH值。结合X射线衍射(XRD)、热重分析(TG-DTG)和扫描电子显微镜(SEM)测试手段,分析其影响机理。结果表明:随着煅烧温度的升高,MgO衍射峰强度增大,MgO活性降低;活性越高的MgO制备的MSPHC净浆凝结时间越短且流动性越差,而活性适中MgO制备的MSPHC具有较好的力学性能。MSPHC最主要的水化产物是水化硅酸镁(M-S-H)凝胶,另外还有Mg(OH)₂和MgKPO₄·6H₂O(MKP)生成,原料轻烧氧化镁粉中的MgCO₃成分不参与体系反应。活性适中的MgO制备的MSPHC在28 d龄期内的水化产物M-S-H凝胶生成量最多,因此硬化体抗压强度最高。活性越高的MgO在MSPHC反应体系中溶解的速度越快,体系水化反应进程速度也越快。

关键词: 水化硅酸镁(M-S-H), MgO活性, 磷酸氢二钾(K₂HPO₄), 力学性能, 水化产物

Abstract: In this paper, the MgO with different reactivity was prepared by the secondary constant temperature calcination of the raw material light burned magnesium oxide powder for 1.5 h at different temperatures. The setting time, fluidity, compressive strength and reaction solution pH value of a new type of magnesium silicate hydrate cement cementitious materials (also known as magnesium silicate phosphate hydrate cement, MSPHC) prepared with different reactivity MgO, silica fume (SF) and dipotassium hydrogen phosphate (K₂HPO₄) were investigated. The mechanism was analyzed through X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG) and scanning electron microscopy (SEM). The results show that with the increase of calcination temperature, the intensity of MgO diffraction peak increases and the reactivity decreases. The faster the setting time and poorer the fluidity of the MSPHC purified slurry prepared by MgO with higher reactivity, while the MSPHC prepared with moderate reactivity MgO can achieve better mechanical properties. The most important hydration product of MSPHC is magnesium silicate hydrate (M-S-H) gel, besides, Mg(OH)₂ and MgKPO₄·6H₂O (MKP) are also generated. The MgCO₃ component in the raw material light burned magnesium oxide powder does not participate in the system reaction.MSPHC prepared by MgO with moderate activity has the highest hydration product M-S-H gel generation within 28 d of age, so the hardened body has the highest compressive strength. The higher the reactivity of MgO in the MSPHC reaction system is, the faster the dissolution rate is, the faster the hydration reaction process is.

Key words: magnesium silicate hydrate (M-S-H), MgO reactivity, dipotassium hydrogen phosphate (K₂HPO₄), mechanical property, hydration product

中图分类号:

TQ172

周凌峰, 林旭健, 王威. MgO活性对新型水化硅酸镁水泥性能的影响[J]. 硅酸盐通报, 2023, 42(1): 57-65.

ZHOU Lingfeng, LIN Xujian, WANG Wei. Effect of MgO Reactivity on Properties of New Magnesium Silicate Hydrate Cement[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2023, 42(1): 57-65.

参考文献

[1] BERNARD E, LOTHENBACH B, RENTSCH D, et al. Formation of magnesium silicate hydrates (M-S-H)[J]. Physics and Chemistry of the Earth, Parts A/B/C, 2017, 99: 142-157.
[2] WEI J X, CHEN Y M, LI Y X. The reaction mechanism between MgO and microsilica at room temperature[J]. Journal of Wuhan University of Technology-Mater Sci Ed, 2006, 21(2): 88-91.
[3] JIN F, AL-TABBAA A. Strength and hydration products of reactive MgO-silica pastes[J]. Cement and Concrete Composites, 2014, 52: 27-33.
[4] TRAN H M, SCOTT A. Strength and workability of magnesium silicate hydrate binder systems[J]. Construction and Building Materials, 2017, 131: 526-535.
[5] ZHANG T T, CHEESEMAN C R, VANDEPERRE L J. Development of low pH cement systems forming magnesium silicate hydrate (M-S-H)[J]. Cement and Concrete Research, 2011, 41(4): 439-442.
[6] LI Z H, YU Q J, CHEN X W, et al. The role of MgO in the thermal behavior of MgO-silica fume pastes[J]. Journal of Thermal Analysis and Calorimetry, 2017, 127(3): 1897-1909.
[7] 李兆恒.MgO-SiO₂-H₂O胶凝体系的反应机制及应用研究[D].广州:华南理工大学,2015.
LI Z H. Reaction mechanisms and application study of MgO-SiO₂-H₂O cementitious system[D]. Guangzhou: South China University of Technology, 2015 (in Chinese).
[8] LI Z H, ZHANG T S, HU J, et al. Characterization of reaction products and reaction process of MgO-SiO₂-H₂O system at room temperature[J]. Construction and Building Materials, 2014, 61: 252-259.
[9] ZHANG T T, VANDEPERRE L J, CHEESEMAN C R. Formation of magnesium silicate hydrate (M-S-H) cement pastes using sodium hexametaphosphate[J]. Cement and Concrete Research, 2014, 65: 8-14.
[10] ZHANG T T, ZOU J, LI Y M, et al. Stabilization/solidification of strontium using magnesium silicate hydrate cement[J]. Processes, 2020, 8(2): 163.
[11] WALLING S A, KINOSHITA H, BERNAL S A, et al. Structure and properties of binder gels formed in the system Mg(OH)₂-SiO₂-H₂O for immobilisation of Magnox sludge[J]. Dalton Transactions (Cambridge, England: 2003), 2015, 44(17): 8126-8137.
[12] ABDEL-GAWWAD H A, EL-ALEEM S A, AMER A A, et al. Combined impact of silicate-amorphicity and MgO-reactivity on the performance of Mg-silicate cement[J]. Construction and Building Materials, 2018, 189: 78-85.
[13] YANG Q B, WU X L. Factors influencing properties of phosphate cement-based binder for rapid repair of concrete[J]. Cement and Concrete Research, 1999, 29(3): 389-396.
[14] 杨全兵,张树青,杨钱荣,等.新型快硬磷酸盐修补材料性能[J].混凝土与水泥制品,2000(4):8-11.
YANG Q B, ZHANG S Q, YANG Q R, et al. Properties of a new-typed reparing material, the rapidly hardened phosphate cement[J]. Chinal Concrete and Cement Products, 2000(4): 8-11 (in Chinese).
[15] 周凌峰.磷酸氢二钾改性水化硅酸镁水泥性能研究[D].福州:福州大学,2021.
ZHOU L F. Study on properties of modified magnesium silicate hydrate cement with dipotassium hydrogen phosphate [D]. Fuzhou: Fuzhou University, 2021 (in Chinese).
[16] LI Z, LIN L D, YU J C, et al. Performance of magnesium silicate hydrate cement modified with dipotassium hydrogen phosphate[J]. Construction and Building Materials, 2022, 323: 126389.
[17] JIN F, AL-TABBAA A. Thermogravimetric study on the hydration of reactive magnesia and silica mixture at room temperature[J]. Thermochimica Acta, 2013, 566: 162-168.
[18] TEMUUJIN J, OKADA K, MACKENZIE K J D. Role of water in the mechanochemical reactions of MgO-SiO₂ systems[J]. Journal of Solid State Chemistry, 1998, 138(1): 169-177.
[19] 王倩,武志红,张国丽,等.MgO活性对MgO -SiO₂-H₂O胶凝体系的影响[J].建筑材料学报,2020,23(4):771-777.
WANG Q, WU Z H, ZHANG G L, et al. Effect of MgO reactivity on MgO-SiO₂-H₂O cementitious system[J]. Journal of Building Materials, 2020, 23(4): 771-777 (in Chinese).
[20] 秦国新,焦宝祥.磷酸镁水泥的研究进展[J].硅酸盐通报,2019,38(4):1075-1079+1085.
QIN G X, JIAO B X. Review of magnesium phosphate cement performance[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(4): 1075-1079+1085 (in Chinese).
[21] 唐小丽,刘昌胜.重烧氧化镁粉的活性测定[J].华东理工大学学报,2001,27(2):157-160.
TANG X L, LIU C S. Activity of dead-burned magnesia[J]. Journal of East China University of Science and Technology, 2001, 27(2): 157-160 (in Chinese).
[22] SOUDÉE E, PÉRA J. Influence of magnesia surface on the setting time of magnesia-phosphate cement[J]. Cement and Concrete Research, 2002, 32(1): 153-157.
[23] 宋强,胡亚茹,王倩,等.MgO活性和养护温度对MgO-SiO₂-H₂O胶凝材料性能的影响[J].硅酸盐学报,2019,47(2):220-227.
SONG Q, HU Y R, WANG Q, et al. Effect of MgO reactivity and curing temperature on properties of MgO-SiO₂-H₂O system[J]. Journal of the Chinese Ceramic Society, 2019, 47(2): 220-227 (in Chinese).
[24] 宋强,胡亚茹,王倩,等.水化硅酸镁胶凝材料研究进展[J].硅酸盐学报,2019,47(11):1642-1651.
SONG Q, HU Y R, WANG Q, et al. Research development of magnesium silicate hydrate cement[J]. Journal of the Chinese Ceramic Society, 2019, 47(11): 1642-1651 (in Chinese).
[25] 潘晓鑫.利用磷酸一氢盐制备新型磷酸镁水泥的机理研究[D].福州:福州大学,2018.
PAN X X. Study on the mechanism of a new-type magnesium phosphate cement prepared with monohydric alkaliine[D]. Fuzhou: Fuzhou University, 2018 (in Chinese).
[26] XIE Y D, LIN X J, PAN X X, et al. Preliminary investigation of the hydration mechanism of MgO-SiO₂-K₂HPO₄ cement[J]. Construction and Building Materials, 2020, 235: 117471.
[27] 杜延男.利用粉煤灰替代硅灰制备水化硅酸镁水泥[D].大连:大连理工大学,2016.
DU Y N. Preparation of magnesium-silicate-hydrate cement by replacing silica fume with pulverized fuel ash[D]. Dalian: Dalian University of Technology, 2016 (in Chinese).
[28] 何子明.水化硅酸镁水泥基砂浆的耐久性研究[D].大连:大连理工大学,2018.
HE Z M. Study on the durability of magnesium silicate hydrate (M-S-H) based mortars[D]. Dalian: Dalian University of Technology, 2018 (in Chinese).
[29] BREW D R M, GLASSER F P. Synthesis and characterisation of magnesium silicate hydrate gels[J]. Cement and Concrete Research, 2005, 35(1): 85-98.