Influence Mechanism of Curing Regimes on Interfacial Transition Zone of Lightweight Ultra-High Performance Concrete

Abstract

This study aims to clarify the effects of curing regimes and lightweight aggregate (LWA) on the morphology, width and mechanical properties of the interfacial transition zone (ITZ) of ultra-high performance concrete (UHPC), and provide reference for the selection of lightweight ultra-high performance concrete (L-UHPC) curing regimes and the pre-wetting degree LWA. The results show that, under the three curing regimes (standard curing, steam curing and autoclaved curing), LWA is tightly bound to the matrix without obvious boundaries. ITZ width increases with the water absorption of LWA and decreases with increasing curing temperature. The ITZ microhardness is the highest when water absorption is 3%, and the microhardness value is more stable with the distance from LWA. Steam and autoclaved curing increase ITZ microhardness compared to standard curing. As LWA pre-wetting and curing temperatures increase, the degree of hydration at the ITZ increases, generating high-density CSH (HD CSH) and ultra-high-density CSH (UHD CSH), and reducing unhydrated particles in ITZ. ITZ micro-mechanical properties are optimized due to hydration products being denser.

Keywords

curing regime / ultra-high performance concrete / lightweight aggregate / interfacial transition zone / meso-mechanical properties / micro-mechanical properties

References

[1] Voo S, Krupashankara M S, Sudarshan T S, et al. Ultrahigh Pressure Consolidation (UHPC) of W-Cu Composites[J]. Materials Science and Technology, 1998, 14(2): 170-174.

[2] Weizu Q, Feng C. A New Ultra-high Performance Concrete-reactive Powder Concrete[J]. Industrial Construction, 1999, 29(4): 16-18.

[3] Yang J. Flexural Behavior of Ultra-high Performance Concrete Beams Prestressed with CFRP Tendons[D], 2007 Changsha: Hunan University.

[4] He Z, Zhu H, Zhang M, et al. Autogenous Shrinkage and Nano-mechanical Properties of UHPC Containing Waste Brick Powder Derived from Construction and Demolition Waste[J]. Construction and Building Materials, 2021, 306: 124 869.

[5] Wu L, Farzadnia N, Shi C, et al. Autogenous Shrinkage of High Performance Concrete: A Review[J]. Construction and Building Materials, 2017, 149: 62-75.

[6] Zhang G, Ge J, Ding Q, et al. Preparation and Formation Mechanism of Lightweight Ultra-high Performance Concrete[J]. Journal of The Chinese Ceramic Society, 2021, 49(02): 381-390.

[7] Li X, Zhang Q, Mao S. Investigation of The Bond Strength and Microstructure of The Interfacial Transition Zone between Cement Paste and Aggregate Modified by Bayer Red Mud[J]. Journal of Hazardous Materials, 2020, 403: 1-21.

[8] Luo Z, Li W, Wang K, et al. Nano/Micromechanical Characterisation and Image Analysis on The Properties and Heterogeneity of ITZs in Geopolymer Concrete[J]. Cement and Concrete Research, 2022, 152: 106 677.

[9] Ollivier J P, Maso J C, Bourdette B. Interfacial Transition Zone in Concrete[J]. Advanced Cement Based Materials, 1995, 2(1): 30-38.

[10] Liao KY, Chang PK, Peng YN, et al. A Study on Characteristics of Interfacial Transition Zone in Concrete[J]. Cement and Concrete Research, 2004, 34(6): 977-989.

[11] Sabin LC. Cement and Concrete[M], 1904 San Francisco: McGraw.

[12] Shenglong Y. Effect of Anhydrous Gypsum of FBC on The Properties of Concrete and Interfacial Transition Zone[D], 2017 Shijiazhuang: Shijiazhuang Tiedao University.

[13] Fu Y, Xie P, Gu P, et al. Significance of Pre-existing Cracks on Nucleation of Secondary Ettringite in Steam Cured Cement Paste[J]. Cement and Concrete Research, 1994, 24(6): 1015-1024.

[14] Zhang H, Ji T, Zeng X, et al. Mechanical Behavior of Ultra-high Performance Concrete (UHPC) Using Recycled Fine Aggregate Cured under Different Conditions and The Mechanism Based on Integrated Microstructural Parameters[J]. Construction and Building Materials, 2018, 192: 489-507.

[15] Xue L, Jiang Y, Yang L, et al. Mechanical Property and Interface Microstructure of Autoclaved Curing Concrete of PHC Pile[J]. Bulletin of the Chinese Ceramic Society, 2015, 34(09): 2662-2667.

[16] Zhang H, Ji T, He B, et al. Performance of Ultra-high Performance Concrete (UHPC) with Cement Partially Replaced by Ground Granite Powder (GGP) under Different Curing Conditions[J]. Construction and Building Materials, 2019, 213(20): 469-482.

[17] Liu J H, Farzadnia N, Shi C J. Effects of Superabsorbent Polymer on Interfacial Transition Zone and Mechanical Properties of Ultra-high Performance Concrete[J]. Construction and Building Materials, 2020, 231: 1-19.

[18] Nie S, Zhang W, Hu S, et al. Improving The Fluid Transport Properties of Heat-cured Concrete by Internal Curing[J]. Construction and Building Materials, 2018, 168: 522-531.

[19] Shi Y, Lv X, Zhou S, et al. Mechanical Properties, Durability, and ITZ Characteristics of Full-grade Dam Concrete Prepared by Aggregates with Surface Rust Stains[J]. Construction and Building Materials, 2021, 305: 124 798.

[20] Lu J, Shen P, Ali Hafiz A, et al. Development of High Performance Lightweight Concrete Using Ultra High Performance Cementitious Composite and Different Lightweight Aggregates[J]. Cement and Concrete Composites, 2021, 124: 104 277.

[21] Huang Q, Qian Z, Hu J, et al. Investigation on The Properties of Aggregate-mastic Interfacial Transition Zones (ITZs) in Asphalt Mixture Containing Recycled Concrete Aggregate[J]. Construction and Building Materials, 2021, 269: 121 257.

[22] Zhang H, Ji T, Zeng X, et al. Mechanical Behavior of Ultra-high Performance Concrete (UHPC) Using Recycled Fine Aggregate Cured under Different Conditions and the Mechanism Based on Integrated Microstructural Parameters[J]. Construction and Building Materials, 2018, 192: 489-507.

[23] Bentz DP, Snyder KA. Protected Paste Volume in Concrete: Extension to Internal Curing Using Saturated Lightweight Fime Aggregate[J]. Cement and Concrete Research, 1999, 29: 1863-1867.

[24] Wu W. Research on Microstructure and Properties of Internal Curing Concrete[D], 2010 Wuhan: Wuhan University of Technology.

[25] Hou D, Zhang W, Sun M, et al. Modified Lucas-Washburn Function of Capillary Transport in The Calcium Silicate Hydrate Gel Pore: A Coarse-grained Molecular Dynamics Study[J]. Cement and Concrete Research, 2020, 136: 106 166.

[26] Yu J, Zheng Q, Hou D, et al. Insights on The Capillary Transport Mechanism in The Sustainable Cement Hydrate Impregnated with Graphene Oxide and Epoxy Composite[J]. Composites Part B: Engineering, 2019, 173: 106 907.

[27] Patel HH, Bland CH, Poole AB. The Microstructure of Concrete Cured at Elevated Temperatures[J]. Cement and Concrete Research, 1995, 25(3): 485-490.

[28] Zou C, Long G, Xie Y, et al. Evolution of Multi-scale Pore Structure of Concrete During Steam-curing Process[J]. Microporous and Mesoporous Materials, 2019, 288: 109 566-109 577.

[29] Pommersheim James M, Clifton James R. Mathematical Modeling of Tricalcium Silicate Hydration[J]. Cement and Concrete Research, 1979, 9(6): 765-770.

[30] Liu J, Liu S, Liu H. Effect of Carbon Nanotubes on Micro Mechanical Properties of Well-Cementing Cement Stone by Nanoindentation Technique[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(04): 1263-1268.

[31] Nie S, Zhang W, Hu S, et al. Improving The Fluid Transport Properties of Heat-cured Concrete by Internal Curing[J]. Construction and Building Materials, 2018, 168: 522-531.

[32] Vandamme M, Ulm F J, Fonollosa P. Nanogranular Packing of C-S-H at Substochiometric Conditions[J]. Cement and Concrete Research, 2010, 40(1): 14-26.

[33] Zanni H, Cheyrezy M, Maret V, et al. Investigation of Hydration and Pozzolanic Reaction in Reactive Powder Concrete (RPC) Using ²⁹Si NMR[J]. Cement and Concrete Research, 1996, 26(1): 93-100.

[34] Shen P, Lu L, He Y, et al. The Effect of Curing Regimes on The Mechanical Properties, Nano-mechanical Properties and Microstructure of Ultra-high Performance Concrete[J]. Cement and Concrete Research, 2019, 118: 1-13.