RADIAL FLOW PERMEAMETER: A PROPOSED APPARATUS TO MEASURE HORIZONTAL HYDRAULIC GRADIENT OF FLY-ASH BASED GEOPOLYMER-SOIL MIX

Abstract

Fly-ash based geopolymer has been proven by many scholars as a viable material to replace cement. Due to its high compressive strength and abundance in industrial areas, it was advocated to partially replace the conventional material in constructing infrastructure, especially in road embankment. Merely consider the load capacity or strength of the materials in designing a road embankment may overlook the durability of the infrastructure. One vital parameter that leads to the deterioration and failure of the road is the permeability of the materials. The flow of water in the road structure comes in a different direction but commonly runs in the horizontal way or longitudinal along the road. Neither ASTM nor AASHTO has established a standard procedure in the determination of the horizontal hydraulic gradient of the soil. Hence, a proposed radial flow permeameter was adopted to determine the permeability of the fly-ash based geopolymer-soil mix. The mixes included dredged soil with 10% (G10), 20% (G20), and 30% (G30) replaced by geopolymer in mass. The interpretation of the test is quantified using a theoretical model and verified using graphical and statistical analysis. The computation was then further verified through anisotropy factor ratio of kh/kv with the data that provided in literature with similar geopolymer-soil blend mix. The outcome of the model displayed the degree of the permeability of G10, G20, and G30 was ×10-4, ×10-6, and ×10- 7 in cm/s, respectively. Lastly, the proposed permeameter was found out to be permissive in determining the horizontal permeability of the specimen with low permeability having a degree of 10-4 or lower.