(e)ISSN 2656-8896 (p)ISSN 2656-890X Journal of Infrastructure and Facility Asset Management – Vol. 6, Spesial Issue 3, January 2024 1 Effect of Stabilization Soil With Fly Ash and Bottom Ash on Characteristics of Residual Soil (Padang-Sicincin Toll Road) Novema Dwi Saputra 1,a) , Trihanyndio Rendy Satrya 2,b) , Ria Asih Aryani Soemitro 3,c) & Sri Hastuti Hardiningsih 4,d) 1) Master’s degree Student, Civil Engineering Department, Sepuluh Nopember Institut of Technology, Surabaya 2) Civil Engineering Departement, Institut Teknologi Sepuluh Nopember, Surabaya 3) Civil Engineering Departement, Institut Teknologi Sepuluh Nopember, Surabaya 4) Project Director, Sicincin – Padang Toll Road Project, PT Hutama Karya (Persero), Padang Correspondent : a) novema.saputra@hutamakarya.com, b) trendysatrya@gmail.com, c) soemitroraa@gmail.com & d) sri.hastuti@hutamakarya.com ABSTRACT Utilization of residual soil in the Trans Sumatra Toll Road Construction Project Padang - Sicincin Section found residual soil types at Sta. 27+000 - 27 + 400 as road embankment and subgrade can be done by stabilization method where the stabilization material used is a mixture of fly ash, bottom ash, and FABA (fly ash+bottom ash). To obtain the optimum percentage of Fly ash, Bottom ash, or FABA (Fly ash Bottom ash) in improving soil behavior, the variations are 10%, 15%, and 20% of bulk density with an incubation period of 0 days, 7 days and 14 days will be selected. Based on the analysis, it is found that stabilization (fly ash, bottom ash, or FABA) results in changes in physical and mechanical residual soil properties with an increase in the CBR value in addition to fly ash at 10% with a CBR value = 4.02%, bottom ash at 20% with a CBR value = 9.49% and FABA at 20% with a CBR value = 14.32% so that the stabilized soil can be used as ordinary backfill soil or preferred backfill soil. Keywords : Soil stabilization, residual soil, fly ash, bottom ash, FABA INTRODUCTION Roads are one of the country's infrastructure assets that must be managed because they can connect the economy of an area with other areas to improve the standard of living and development of an area. According to (Suprayitno & Soemitro, 2018), infrastructure asset management is the science, knowledge, or program for managing infrastructure so that it can perform its functions sustainably, effectively, and efficiently. Therefore, roads must be built and managed using the principles of infrastructure asset management. The Trans-Sumatra Toll Road, spanning 2,818 kilometers, is a planned toll road network in Indonesia designed to link cities across the island of Sumatra, extending from Lampung to Aceh. Planning the construction of this road often passes through locations of problematic soils. Problematic soil is one of the important factors that cause the decline or disruption of the stability of constructions such as roads and bridges. The soil in road construction functions as a subgrade that supports the construction load and traffic above it. This was found in toll road construction in West Sumatra, in particular at Sta. 27+000 - 27 + 400 Padang - Sicincin Toll Road Construction Project which has contours of hills and mountains Figure 1. So that a lot of cutting or dredging of native soil is carried out at that location. Even some locations require high embankment to achieve the planned elevation conditions.