摘要At present, chemical admixtures are usually added in concrete mixtures when all ingredients are mixed together either by one-time input or in batches for various purposes. The present study proposes a new method for lightweight aggregate (LWA) concrete or combined aggregate concrete, wherein porous and hydrophilic LWA are presoaked in chemical admixture solution with the appropriate concentration. Poly carboxylic acid-based-super plasticizer and setting retarder were prepared and added individually in combined aggregate concrete in different ways, as follows:(1) one-time direct admixing into a concrete mixer; (2) blending in concrete mixture in batches; and (3) absorbing into LWA particles in advance. Time-dependent slump and setting times of concrete mixtures were investigated, which proved that chemical admixtures can be stored in porous aggregate particles beforehand by means of presoaking. LWA, with the internal pores as sustained-release capsules, become temporary carriers of water and chemical admixtures. Once relative humidity in the concrete mixture falls, the molecules of chemical admixtures gradually move out with water migration to play a persistent part in, for example, successful slump loss reduction or setting time adjustment.
Abstract：At present, chemical admixtures are usually added in concrete mixtures when all ingredients are mixed together either by one-time input or in batches for various purposes. The present study proposes a new method for lightweight aggregate (LWA) concrete or combined aggregate concrete, wherein porous and hydrophilic LWA are presoaked in chemical admixture solution with the appropriate concentration. Poly carboxylic acid-based-super plasticizer and setting retarder were prepared and added individually in combined aggregate concrete in different ways, as follows:(1) one-time direct admixing into a concrete mixer; (2) blending in concrete mixture in batches; and (3) absorbing into LWA particles in advance. Time-dependent slump and setting times of concrete mixtures were investigated, which proved that chemical admixtures can be stored in porous aggregate particles beforehand by means of presoaking. LWA, with the internal pores as sustained-release capsules, become temporary carriers of water and chemical admixtures. Once relative humidity in the concrete mixture falls, the molecules of chemical admixtures gradually move out with water migration to play a persistent part in, for example, successful slump loss reduction or setting time adjustment.
基金资助:Supported by the National Natural Science Foundation of China(No.51302020); The Technology Plan Project of Ministry of Transport of China (No. 2015319825180)
陈瑜, 邓怡帆, 刘洋. 轻骨料对化学外加剂的“载体”与“缓释”作用研究[J]. Journal of Highway and Transportation Research and Development, 2016, 10(3): 67-73.
CHEN Yu, DENG Yi-fan, LIU Yang. Carrier and Delayed Release Properties of Lightweight Aggregates for Chemical Admixtures. Journal of Highway and Transportation Research and Development, 2016, 10(3): 67-73.
[1] CHEESEMAN C R, MAKINDE A, BETHANIS S. Properties of Lightweight Aggregate Produced by Rapid Sintering of Incinerator Bottom Ash[J]. Resources, Conservation and Recycling, 2005, 43(1):147-162.
[2] SENGUL O, AZIZIB S, KARAOSMANOGLU F. Effect of Expanded Perlite on the Mechanical Properties and Thermal Conductivity of Lightweight Concrete[J]. Energy and Buildings, 2011, 43(3):671-676.
[3] KOCKALN U, OZTURANT. Optimization of Properties of Fly Ash Aggregates for High-strength Lightweight Concrete Production[J]. Materials and Design, 2011, 32(11):3586-3593.
[4] YANG Yong, NIE Jian-guo, YANG Wen-ping. Experimental Study on Mechanical Behavior and Vibration Chara-cteristic of Re-entrant Through Profiled Steel Sheeting-lightweight Concrete Composite Slab[J]. Journal of Building Structures, 2008, 28(6):48-55. (in Chinese)
[5] TORRES M L, GARCÍA-RUIZ P A. Lightweight Pozzolanic Materials Used in Mortars:Evaluation of Their Influence on Density, Mechanical Strength and Water Absorption[J]. Cement and Concrete Composites, 2009, 31(1):114-119.
[6] LO T Y, TANG W C, CUI H Z. Effects of Aggregate Properties on Lightweight Concrete[J]. Building and Environment, 2007, 42(7):3025-3029.
[7] GESOĞLU M, GVNEYISI E, ÖZTURAN T. Permeation Characteristics of Self Compacting Concrete Made with Partially Substitution of Natural Aggregates with Roundedlightweight Aggregates[J]. Construction and Building Materials, 2014(59):1-9.
[8] BENTUR A, IGARASHI S, KOVLER K. Prevention of Autogenous Shrinkage in High-Strength Concrete by Internal Aggregates Original Research Artice[J]. Cement and Concrete Research, 2001, 31(11):1587-1591.
[9] HENKENSIEFKEN R, BENTZ D, NANTUNG T, et al. Volume Change and Cracking in Internally Cured Mixtures Made with Saturated Lightweight Aggregate Under Sealed and Unsealed Conditions[J]. Cement and Concrete Composites, 2009, 31(7):427-437.
[10] BENTZ D P. Influence of Internal Curing Using Lightweight Aggregates on Interfacial Transition Zone Percolation and Chloride Ingress in Mortars[J]. Cement and Concrete Composites, 2009, 31(5):285-289.
[11] HENKENSIEFKEN R, NANTUNG T, WEISS J. Saturated Lightweight Aggregate for Internal Curing in Low W/C Mixtures:Monitoring Water Movement Using X-Ray Absorption[J]. Strain, 2011(47):432-441.
[12] MARUYAMA I, TERAMOTO A. Effect of Water-retaining Lightweight Aggregate on the Reduction of Thermal Expansion Coefficient in Mortar Subject to Temperature Histories[J]. Cement and Concrete Composites, 2012, 34(10):1124-1129.
[13] HU Shu-guang, WANG Fa-zhou, DING Qing-jun. Influence of Water Abosption and Pre-wetted Method of Lightweight Aggregate on the Workability of Concrete[J]. Journal of Huazhong University of Science and Technology:Urban Science Edition, 2002, 20(2):1-4. (in Chinese)
[14] ALGHAMRI R, KANELLOPOULOS A, AL-TABBAA A. Impregnation and Encapsulation of Lightweight Aggregates for Self-healing Concrete[J]. Construction and Building Materials, 2016, 124(9):910-921.
[15] CASTRO J, KEISER L, GOLIAS M. Absorption and Desorption Properties of Fine Lightweight Aggregate for Application to Internally Cured Concrete Mixtures[J]. Cement & Concrete Composites, 2011, 33(8):1001-1008.
[16] BOGAS J A, GOMES A. Compressive Behavior and Failure Modes of Structural Lightweight Aggregate Concrete-characterization and Strength Prediction[J]. Materials & Design, 2013, 46(4):832-841.
[17] SARABÈR A, OVERHOF R, GREEN T, et al. Artificial Lightweight Aggregates as Utilization for Future Ashes-a Case Study[J]. Waste Management, 2012, 32(1):144-152.
[18] HUSEM M. The Effect of Bond Strengths between Lightweight and Ordinary Aggregate Mortar, Aggregate-cement Paste on the Mechanical Properties of Concrete[J]. Materials Science and Engineering, 2003, 363(1):152-158.
[19] CHOISE-JIN, YANGKEUN-HYEOK, SIMJAE-Il, et al. Direct Tensile Strength of Lightweight Concrete with Different Specimen Depths and Aggregate Sizes[J]. Construction and Building Materials, 2014(63):132-141.
[20] CUSSON D, HOOGEVEEN T. Internal Curing of High-performance Concrete with Pre-soaked Fine Lightweight Aggregate for Prevention of Autogenous Shrinkage Cracking[J]. Cement and Concrete Research, 2008, 38(6):757-765.
[21] BENTUR A, IGARASHI S, KOVLER K. Prevention of Autogenous Shrinkage in High-strength Concrete by Internal Curing Using Wet Lightweight Aggregates[J]. Cement and Concrete Research, 2011, 31(11):1587-1591.
[22] GESOĞLU M, ÖZTURAN T, GVNEYISI E. Shrinkage Cracking of Lightweight Concrete Made with Cold-bonded Fly Ash Aggregates[J]. Cement and Concrete Research, 2004, 34(7):1121-1130.
[23] KUCHARCZYKOVÁ B, KERŠNER Z, POSPÍCHAL O. The Porous Aggregate Pre-soaking in Relation to the Freeze-thaw Resistance of Lightweight Aggregate Concrete[J]. Construction and Building Materials, 2012(30):761-766.
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常柱刚, 王林凯, 夏飞龙. 基于CV NewMark-b法桥梁风致振动FSI数值模拟[J]. Journal of Highway and Transportation Research and Development, 2019, 13(2): 28-37.
2016, Vol. 10 
