Mechanical Properties of Alkali-Activated Slag/Fly Ash Paste/Mortar

Abstract

Abstract: Study on the mechanical properties of alkali-activated materials is able to promote its practical application in engineering. In this paper, the effects of slag content and fine aggregate content on the compressive strength, elastic modulus and stress-strain curves of alkali-activated paste/mortar were investigated. The results show that the addition of slag significantly improves the compressive strength and elastic modulus of alkali-activated paste/mortar. The addition of fine aggregate reduces the compressive strength while improves the elastic modulus. The elastic modulus of alkali-activated slag/fly ash paste ranges from 12.83 GPa to 19.53 GPa at 28 d. The elastic modulus of alkali-activated slag/fly ash mortar ranges from 18.72 GPa to 23.10 GPa at 28 d. When the amount of fine aggregate is 40% (mass fraction), the peak stress and peak strain decrease obviously while elastic modulus increases. The piecewise equation is used to fit the stress-strain curves of alkali-activated slag/fly ash paste/mortar. The fitting curves are in good agreement with the measured curves. The fitting results indicate that the stress-strain curves of alkali-activated slag/fly ash paste/mortar become steeper with the increase of slag content and the curing age, reflecting the brittleness of materials, which is consistent with the rising curves.

Key words: alkali-activated material, slag, fly ash, mechanical property, stress-strain, compressive strength, elastic modulus, peak strain

CLC Number:

TU57⁺8.1

ZHUANG Peizhen, MA Yuwei, LUO Tiantian, LIU Weisen, FU Jiyang. Mechanical Properties of Alkali-Activated Slag/Fly Ash Paste/Mortar[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(10): 3578-3589.

References

[1] (法)约瑟夫·戴维德维斯.地聚合物化学及应用[M].王克俭,译.北京:国防工业出版社,2011:10.
(France) DAVIDOVITS J. Geopolymer chemistry and applications[M]. WANG K J, trans. Beijing: National Defence Industry Press, 2011: 10 (in Chinese).
[2] PROVIS J L. Alkali-activated materials[J]. Cement and Concrete Research, 2018, 114: 40-48.
[3] TEMUUJIN J, MINJIGMAA A, DAVAABAL B, et al. Utilization of radioactive high-calcium Mongolian fly ash for the preparation of alkali-activated geopolymers for safe use as construction materials[J]. Ceramics International, 2014, 40(10): 16475-16483.
[4] NG T S, AMIN A L, FOSTER S J. The behaviour of steel-fibre-reinforced geopolymer concrete beams in shear[J]. Magazine of Concrete Research, 2013, 65(5): 308-318.
[5] DAVIDOVITS J. Geopolymer chemistry and applications[M]. 3rd ed. Saint-Quentin: Institut Géopolymère, Geopolymer Institute, Saint-Quentin, 2008.
[6] 郭晓潞,施惠生.热活化污泥-高钙粉煤灰地聚合物的性能与机理[J].同济大学学报(自然科学版),2012,40(8):1229-1233.
GUO X L, SHI H S. Performances and mechanism of geopolymers prepared from thermally-treated sludge and high-calcium fly ash[J]. Journal of Tongji University (Natural Science), 2012, 40(8): 1229-1233 (in Chinese).
[7] NAZARI A, BAGHERI A, RIAHI S. Properties of geopolymer with seeded fly ash and rice husk bark ash[J]. Materials Science and Engineering: A, 2011, 528(24): 7395-7401.
[8] ZHANG M, EL-KORCHI T, ZHANG G P, et al. Synthesis factors affecting mechanical properties, microstructure, and chemical composition of red mud-fly ash based geopolymers[J]. Fuel, 2014, 134: 315-325.
[9] COLLINS F G, SANJAYAN J G. Workability and mechanical properties of alkali activated slag concrete[J]. Cement and Concrete Research, 1999, 29(3): 455-458.
[10] DOUGLAS E, BILODEAU A, MALHOTRA V. Properties and durability of alkali-activated slag concrete[J]. ACI Materials Journal, 1992, 89(5): 509-516.
[11] YANG K H, CHO A R, SONG J K. Effect of water-binder ratio on the mechanical properties of calcium hydroxide-based alkali-activated slag concrete[J]. Construction and Building Materials, 2012, 29: 504-511.
[12] FERNÁNDEZ-JIMÁNEZ A M, PALOMO A, LÓPEZ-HOMBRADOS C. Engineering properties of alkali-activated fly ash concrete[J]. ACI Materials Journal, 2006, 103(2): 106-112.
[13] JOSEPH B, MATHEW G. Influence of aggregate content on the behavior of fly ash based geopolymer concrete[J]. Scientia Iranica, 2012, 19(5): 1188-1194.
[14] THOMAS R J, PEETHAMPARAN S. Alkali-activated concrete: engineering properties and stress-strain behavior[J]. Construction and Building Materials, 2015, 93: 49-56.
[15] 国家质量技术监督局.水泥胶砂强度检验方法(ISO法):GB/T 17671—1999[S].北京:中国标准出版社,1999.
State Administration of Quality and Technical Supervision. Method of testing cements—determination of strength (ISO method): GB/T 17671—1999[S]. Beijing: China Standard Press, 1999 (in Chinese).
[16] 中华人民共和国住房和城乡建设部.混凝土物理力学性能试验方法标准:GB/T 50081—2019[S].北京:中国建筑工业出版社,2019.
Ministry of Housing and Urban-Rural Development of the People's Republic of China. Standard for test methods of concrete physical and mechanical properties: GB/T 50081—2019[S]. Beijing: China Architecture & Building Press, 2019 (in Chinese).
[17] PUERTAS F, MARTÍNEZ-RAMÍREZ S, ALONSO S, et al. Alkali-activated fly ash/slag cements: strength behaviour and hydration products[J]. Cement and Concrete Research, 2000, 30(10): 1625-1632.
[18] FANG G H, HO W K, TU W L, et al. Workability and mechanical properties of alkali-activated fly ash-slag concrete cured at ambient temperature[J]. Construction and Building Materials, 2018, 172: 476-487.
[19] VAN DEVENTER J S J, PROVIS J L, DUXSON P, et al. Reaction mechanisms in the geopolymeric conversion of inorganic waste to useful products[J]. Journal of Hazardous Materials, 2007, 139(3): 506-513.
[20] 郑文忠,邹梦娜,王英.碱激发胶凝材料研究进展[J].建筑结构学报,2019,40(1):28-39.
ZHENG W Z, ZOU M N, WANG Y. Literature review of alkali-activated cementitious materials[J]. Journal of Building Structures, 2019, 40(1): 28-39 (in Chinese).
[21] HANY E, FOUAD N, ABDEL-WAHAB M, et al. Compressive strength of mortars incorporating alkali-activated materials as partial or full replacement of cement[J]. Construction and Building Materials, 2020, 261: 120518.
[22] FANG G H, WANG Q, ZHANG M Z. Micromechanical analysis of interfacial transition zone in alkali-activated fly ash-slag concrete[J]. Cement and Concrete Composites, 2021, 119: 103990.
[23] FERNÁNDEZ-JIMÁNEZ A, PALOMO A. Composition and microstructure of alkali activated fly ash binder: effect of the activator[J]. Cement and Concrete Research, 2005, 35(10): 1984-1992.
[24] 吴有明.活性粉末混凝土(RPC)受压应力-应变全曲线研究[D].广州:广州大学,2012:33-39.
WU Y M. Study of the reactive powder concrete (RPC) about compressive stress-strain curve[D]. Guangzhou: Guangzhou University, 2012: 33-39 (in Chinese).
[25] 过镇海,郭玉涛,徐焱,等.混凝土非线弹性正交异性本构模型[J].清华大学学报(自然科学版),1997,37(6):78-81.
GUO Z H, GUO Y T, XU Y, et al. Nonlinear elastic orthotropic constitutive model for concrete[J]. Journal of Tsinghua University (Science and Technology), 1997, 37(6): 78-81 (in Chinese).
[26] 谭彬.活性粉末混凝土受压应力应变全曲线的研究[D].长沙:湖南大学,2007:44-46.
TAN B. Research on stress-strain curves of reactive powder concrete under uniaxial compression[D]. Changsha: Hunan University, 2007: 44-46 (in Chinese).
[27] RANGAN B V, HARDJITO D, WALLAH S E, et al. Studies on fly ash-based geopolymer concrete[C]//Proceedings of the world congress geopolymer, Saint Quentin, France, 2005: 133-137.
[28] COLLINS F, SANJAYAN J G. Microcracking and strength development of alkali activated slag concrete[J]. Cement and Concrete Composites, 2001, 23(4/5): 345-352.
[29] 陈宗平,徐金俊,郑华海,等.再生混凝土基本力学性能试验及应力应变本构关系[J].建筑材料学报,2013,16(1):24-32.
CHEN Z P, XU J J, ZHENG H H, et al. Basic mechanical properties test and stress-strain constitutive relations of recycled coarse aggregate concrete[J]. Journal of Building Materials, 2013, 16(1): 24-32 (in Chinese).
[30] ALASADY A, KOTHARI A, PROVIS J, et al. The effect of blast furnace slag/fly ash ratio on setting, strength, and shrinkage of alkali-activated pastes and concretes[J]. Frontiers in Materials, 2019, 6: 9.