Effect of Sodium Alginate on the Mechanical Properties and Microstructure of Metakaolin-Based Geopolymers

Abstract

Metakaolin (MK) and sodium alginate (SA) were employed as raw materials to prepare SA-MK geopolymers, which were inorganic/organic composites. The microscopic morphologies, mineral phases, and chemical bonds of these composites were examined using mercury intrusion porosimetry, X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. And low-field nuclear magnetic resonance (LF-NMR) experiments were conducted to study the water forms at different curing ages. In addition, fluidity, bond strength, and compressive strength measurements were conducted to determine their macroscopic mechanical properties. The obtained results revealed that SA addition improved the viscosity and adhesion of the geopolymer slurry and increased the adhesion strength and density of the geopolymers with low Si/Al ratios. Nevertheless, it also reduced the fluidity of the mixed slurry and shortened the operation time. Adding the optimal amount of SA increased the compressive strength of the MK-based geopolymers. At a SA content of 1.5 wt%, the 7-day strength of the geopolymer reached its maximum value of 28.3 MPa, which was 74.6% higher than that achieved without the addition of SA. Furthermore, the presence of SA changed the water distribution and the pore structure of the MK-based geopolymers, which strongly affected their mechanical properties.

References

[1] FéreyG. Hybrid Porous Solids: Past, Present, Future[J]. Chem. Soc. Rev., 2008, 37(1): 191-214

[2] ProvisJ L, Van DeventerJ S JGeopolymers: Structures, Processing, Properties and Industrial Applications, 2009, Amsterdam, Elsevier M]

[3] ZhangJ, JinC, WangB, et al.. Study on the Micro-Rheological Properties of Fly Ash-Based Cement Mortar[J]. Constr. Build. Mater., 2024, 442: 137 664

[4] RongX, WangZ, XingX, et al.. Review on the Adhesion of Geopolymer Coatings[J]. ACS Omega, 2021, 6(8): 5108-5112

[5] BernalS A, RodríguezE D, Mejía de GutiérrezR, et al.. Mechanical and Thermal Characterisation of Geopolymers Based on Silicate-Activated Metakaolin/slag Blends[J]. J. Mater. Sci., 2011, 46(16): 5477-5486

[6] ZhangM, XuH, ZezeA L P, et al.. Metakaolin-Based Geopolymer Composites Modified by Epoxy Resin and Silane: Mechanical Properties and Organic-Inorganic Interaction Mechanism[J]. Appl. Clay Sci., 2023, 232: 106 767

[7] RashadA M, ZeedanS R. The Effect of Activator Concentration on the Residual Strength of Alkali-activated Fly Ash Pastes Subjected to Thermal Load[J]. Constr. Build. Mater., 2011, 25(7): 3098-3107

[8] LahotiM, TanK H, YangE H. A Critical Review of Geopolymer Properties for Structural Fire-Resistance Applications[J]. Constr. Build. Mater., 2019, 221: 514-526

[9] ZhangZ, YaoX, WangH. Potential Application of Geopolymers as Protection Coatings for Marine Concrete III. Field Experiment[J]. Appl. Clay Sci., 2012, 67: 57-60

[10] RanjbarN, ZhangM. Fiber-Reinforced Geopolymer Composites: A Review[J]. Cement Concrete Comp., 2020, 107: 103 498

[11] TimakulP, RattanaprasitW, AungkavattanaP. Improving Compressive Strength of Fly Ash-Based Geopolymer Composites by Basalt Fibers Addition[J]. Ceram. Int., 2016, 42(5): 6288-6295

[12] BhuttaA, FarooqM, ZanottiC, et al.. Pull-Out Behavior of Different Fibers in Geopolymer Mortars: Effects of Alkaline Solution Concentration and Curing[J]. Mater. Struct., 2017, 50(1): 1-13

[13] RovielloG, RicciottiL, TaralloO, et al.. Innovative Fly Ash Geopolymer-Epoxy Composites: Preparation, Microstructure and Mechanical Properties[J]. Materials, 2016, 9(6): 461

[14] ZhangS, GongK, LuJ. Novel Modification Method for Inorganic Geopolymer by Using Water Soluble Organic Polymers[J]. Mater. Lett., 2004, 58(7–8): 1292-1296

[15] LiZ, ChenR, ZhangL. Utilization of Chitosan Biopolymer to Enhance Fly Ash-Based Geopolymer[J]. J. Mater. Sci., 2013, 48(22): 7986-7993

[16] RovielloG, MennaC, TaralloO, et al.. Preparation, Structure and Properties of Hybrid Materials Based on Geopolymers and Polysiloxanes[J]. Mater. Design, 2015, 87: 82-94

[17] ZhangY J, WangY C, LiS. Mechanical Performance and Hydration Mechanism of Geopolymer Composite Reinforced by Resin[J]. Mat. Sci. Eng. A-Struct., 2010, 527(24–25): 6574-6580

[18] DuJ, BuY, ShenZ, et al.. Effects of Epoxy Resin on the Mechanical Performance and Thickening Properties of Geopolymer Cured at Low Temperature[J]. Mater. Design, 2016, 109: 133-145

[19] AlgothmiW M, BandaruN M, YuY, et al.. Alginate-Graphene Oxide Hybrid Gel Beads: An Efficient Copper Adsorbent Material[J]. J. Colloid. Interf. Sci., 2013, 397: 32-38

[20] GeY, CuiX, LiaoC, et al.. Facile Fabrication of Green Geopolymer/Alginate Hybrid Spheres for Efficient Removal of Cu (II) in Water: Batch and Column Studies[J]. Chem. Eng. J., 2017, 311: 126-134

[21] KhanM I, AzizliK, SufianS, et al.. Sodium Silicate-Free Geopolymers as Coating Materials: Effects of Na/Al and Water/Solid Ratios on Adhesion Strength[J]. Ceram. Int., 2015, 41(2): 2794-2805

[22] MoB, ZhuH, CuiX, et al.. Effect of Curing Temperature on Geopolymerization of Metakaolin-Based Geopolymers[J]. Appl. Clay Sci., 2014, 99: 144-148

[23] StevesonM, Sagoe-CrentsilK. Relationships Between Composition, Structure and Strength of Inorganic Polymers[J]. J. Mater. Sci., 2005, 40(8): 2023-2036

[24] ChengY H, YunM L, AbdullahM, et al.. Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses[J]. Sci. Rep.-UK., 2017, 7(1): 1-11

[25] MadavarapuS BFTIR Analysis of Alkali Activated Slag and Fly Ash Using Deconvolution Techniques, 2014, Arizona, Arizona State University[M]

[26] AssaediH, ShaikhF, LowI M. Effect of Nano-Clay on Mechanical and Thermal Properties of Geopolymer[J]. J. Asian. Ceram. Soc., 2016, 4(1): 19-28

[27] LiZ, ZhangS, ZuoY, et al.. Chemical Deformation of Metakaolin Based Geopolymer[J]. Cement Concrete Res., 2019, 120: 108-118

[28] ProvisJ L, LukeyG C, van DeventerJ S. Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results[J]. Chem. Mater., 2005, 17(12): 3075-3085

[29] RowlesM, O’connorB. Chemical Optimisation of the Compressive Strength of Aluminosilicate Geopolymers Synthesised by Sodium Silicate Activation of Metakaolinite[J]. J. Mater. Chem., 2003, 13(5): 1161-1165

[30] YipC K, LukeyG C, Van DeventerJ S. Effect of Blast Furnace Slag Addition on Microstructure and Properties of Metakaolinite Geopolymeric Materials[J]. Br. Ceram. Trans., 2004, 153: 187-209

[31] KahlenbergV, BohnH. Crystal Structure of Hexagonal Trinepheline; a New Synthetic NaAlSiO₄ Modification[J]. Am. Mineral., 1998, 83(5–6): 631-637

RIGHTS & PERMISSIONS

Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature