Abstract
The weak subgrade soil is one of the major challenges for civil engineering applications such as roads and foundations. This study aims to find out the influence of fly ash-based geopolymer on the strength of weak soil to fulfill the requirements of the subgrade layer in the pavement structure. Fly ash particles of class F was used as a raw material for geopolymer synthesis. The alkaline liquid consists of the Sodium hydroxide (NaOH) at 8 molars solution and Sodium silicate Na2Sio3 in liquid form and the ratio of NaOH:Na2Sio3 remained constant at 60:40 by weight. Low plasticity sandy silt was utilized in the study and stabilized using various proportions of fly ash (5, 10, 15, 20, 25, and 30%). Laboratory investigation involves the compaction properties of soil-fly ash mixtures in addition to the mechanical properties including the Unconfined Compressive Strength (UCS) test and the Indirect Tensile Strength (ITS) test. The UCS test results revealed that the compressive strength of the soil greatly improved after adding the fly ash-based geopolymer and 20% of fly ash content achieved the highest UCS at 28 days of curing time. The ITS test results exhibited a progressive increase in the tensile strength of the soil with fly ash geopolymer, which corresponds to a great resistance for cracking in the soil. Geopolymer gel was observed in the stabilized soil, as confirmed by the SEM analysis.
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References
Adhikari S (2017) Mechanical properties of soil-RAP-geopolymer for the stabilization of road base/subbase. University of Louisiana at Lafayette
Amulya S, Ravi Shankar AU, Praveen M (2018) Stabilisation of lithomargic clay using alkali activated fly ash and ground granulated blast furnace slag. Int J Pavement Eng 1–8
Bagheri A et al (2017) Alkali activated materials vs geopolymers: role of boron as an eco-friendly replacement. Constr Build Mater 146:297–302
Burmister DM et al (1944) The theory of stress and displacements in layered systems and applications to the design of airport runways. In: Highway research board proceedings
Canfield GM et al (2014) The role of calcium in blended fly ash geopolymers. J Mater Sci 49(17):5922–5933
Cristelo N et al (2012) Effect of calcium content on soil stabilisation with alkaline activation. Constr Build Mater 29:167–174
Cristelo N et al (2013) Effects of alkaline-activated fly ash and portland cement on soft soil stabilisation. Acta Geotech 8(4):395–405
Cristelo N, Glendinning S, Teixeira Pinto A (2011) Deep soft soil improvement by alkaline activation. Proc Inst Civil Eng-Ground Improv 164(2):73–82
Davidovits J (2015) False values on CO2 emission for geopolymer cement/concrete published in scientific papers. Technical paper, no 24
Davidovits J (2017) Geopolymers: ceramic-like inorganic polymers. J Ceram Sci Technol 8(3):335–350
Dungca JR, II E (2018) Fly-ash-based geopolymer as stabilizer for silty sand embankment materials. Int J 14(46):143–149
González A et al (2013) Laboratory fatigue life of cemented materials in Australia. Road Mater Pavement Des 14(3):518–536. https://doi.org/10.1080/14680629.2013.779300
Hardjito D, Rangan BV (2005) Development and properties of low-calcium fly ash-based geopolymer concrete
Khater HM (2011) Effect of calcium on geopolymerization of aluminosilicate wastes. J Mater Civil Eng 24(1):92–101
Link RE et al (2001) California bearing ratio behavior of soil/fly ash mixtures. J Test Eval 29:220–226. https://doi.org/10.1520/jte12249j
Muhaimeed AS et al (2014) Classification and distribution of Iraqi soils. Int J Agric Innov Res 2(6):997–1002
Phani Kumar BR, Sharma RS (2004) Effect of fly ash on engineering properties of expansive soils. J Geotech Geoenviron Eng 130(7):764–767
Rangan B (2009) Engineering properties of geopolymer concrete. In: Geopolymers: structures, processing, properties and industrial applications, pp 211–226. https://doi.org/10.1533/9781845696382.2.211
Santos F et al (2011) Geotechnical properties of fly ash and soil mixtures for use in highway embankments. In: Proceedings of the world of coal ash (WOCA) conference, Denver, USA, pp 125–136
Slaty F et al (2015) Durability of alkali activated cement produced from kaolinitic clay. Appl Clay Sci 104:229–237
Temuujin JV, Van Riessen A, Williams R (2009) Influence of calcium compounds on the mechanical properties of fly ash geopolymer pastes. J Hazard Mater 167(1–3):82–88
Thompson MR (1966) Split-1”’ensile strength of lime-stabilized soils
Wijaya SW, Hardjito D (2016) Factors affecting the setting time of fly ash-based geopolymer. In: Materials science forum. Trans Tech Publications, pp 90–97
Wright PJF (1955) Comments on an indirect tensile test on concrete cylinders. Mag Concr Res 7(20):87–96
Yaghoubi M et al (2018) Effects of industrial by-product based geopolymers on the strength development of a soft soil. Soils Found 58(3):716–728
Yip CK, Van Deventer JSJ (2003) Microanalysis of calcium silicate hydrate gel formed within a geopolymeric binder. J Mater Sci 38(18):3851–3860
Yip CK, Lukey GC, van Deventer JSJ (2005) The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation. Cement Concr Res 35(9):1688–1697
ASTM C618-12 (2012) Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete. ASTM International, West Conshohocken. www.astm.org
ASTM D4318-10 (2010) Standard test methods for liquid limit, plastic limit, and plasticity index of soils. ASTM International, West Conshohocken. www.astm.org
ASTM D854-14 (2014) Standard test methods for specific gravity of soil solids by water pycnometer. ASTM International, West Conshohocken. www.astm.org
ASTM D2487-11 (2011) Standard practice for classification of soils for engineering purposes (unified soil classification system). ASTM International, West Conshohocken. www.astm.org
ASTM D1557-12 (2012) Standard test methods for laboratory compaction characteristics of soil using modified effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)). ASTM International, West Conshohocken. www.astm.org
ASTM D4219-08 (2008) Standard test method for unconfined compressive strength index of chemical- grouted soils (withdrawn 2017). ASTM International, West Conshohocken. www.astm.org
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Kwad, N.F., Abdulkareem, A.H., Ahmed, T.M. (2020). The Effect of Fly Ash Based Geopolymer on the Strength of Problematic Subgrade Soil with High CaO Content. In: Raab, C. (eds) Proceedings of the 9th International Conference on Maintenance and Rehabilitation of Pavements—Mairepav9. Lecture Notes in Civil Engineering, vol 76. Springer, Cham. https://doi.org/10.1007/978-3-030-48679-2_51
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