COMPRESSIVE STRENGTH OF SOIL CEMENT BASE MIXED WITH FLY ASH – BASED GEOPOLYMER

At present, the improvement of compressive strength of soil using the Portland cement is widely used for roads and embankments, however, it has an enormous impact on the environment. Geopolymer cement is a material that can replace Portland cement and has less impact on the environment. Therefore, this research aims to study lateritic soil improvement by using Fly ash-based geopolymer materials. Percentage of fly ash was 1.5, 3, 5, 7, 10, 15 and 20 % by weight. Specimens were prepared by the method of modified Proctor compaction test. Curing was done at 40 o C for 24 hours and immerse in water for 2 hours before the tests. Unconfined compressive strength tests at 7, 14 and 28 days were performed. The results showed that the 5% fly ash by weight and NaOH/Na2SiO3 ratio of 1/1 was leading to the improvement of compressive strength above 17.5 ksc which is higher than the standard No. DH-S. 204/2533 Soil cement base.