Volume 31, No. 04, Month OCTOBER, Year 2021, Pages 675 - 684

Strength and durability of lateritic soil mixed with fly ash geopolymer as a non-bearing interlocking block

Rachata Prommapong, Cherdsak Suksiripattanapong, Sermsak Tiyasangthong, Wisitsak Tabyang

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This research studies the strength and durability of lateritic soil mixed with fly ash geopolymer. The following parameters, i.e. the ratio of lateritic soil (LS) to fly ash (FA) at 3 : 1; the ratio of sodium silicate (Na2SiO3) to sodium hydroxide (NaOH) at 80 : 20, 70 : 30, and 50 : 50; the concentration of NaOH of at 1, 3 and 5 Molar (M); and curing time of 7, 14, 28, 60, and 90 days were investigated in this study. The compaction test, the unconfined compressive strength (UCS), the flexural strength (FS), and the wet–dry cycles of LS mixed with FA geopolymer were evaluated. The test results showed that Na2SiO3 : NaOH ratio and the concentration of NaOH had an effect on dry unit weight, UCS, and FS. The maximum dry unit weight and the optimum liquid alkaline content of the sample were 19.01 kN/m3 and 18% respectively. The maximum UCS and FS of the sample of Na2SiO3 : NaOH at the ratio of 80 : 20 and the concentration of NaOH of 5 Molar at 28 days curing were 6.55 and 2.70 MPa respectively. This maximum UCS was higher than the standard of non-bearing interlocking block at 2.62 times. The amount of NaOH had an effect on UCS, water absorption and weight loss of the sample. The higher NaOH content could leached silica when sample was heated, causing more dense matrix structure.


Laterite Soil, Fly Ash, Unconfined Compressive Strength, Wet–dry Cycles, Geopolymer


Published by : King Mongkut's University of Technology North Bangkok
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