Expansive soils have high swelling and shrinkage potentials, which may cause damage to road structures. Therefore, stabilization is required. One method of stabilization is to use lime and spent catalysts with the aim of increasing carrying capacity and reducing swelling. Spent catalyst is a petroleum processing waste and classified as pozzolanic material. The addition of lime and spent catalysts can increase the CBR value and reduce swelling of soils. The results of this study indicate that the maximum increase in soaked CBR and unsoaked CBR values occurred in soil mixtures with optimum lime content and 12% spent catalyst with 7 days of curing. While the soil mixture with optimum lime content and 12% spent catalyst, with 7 days of curing, is the best mixture that produces soaked CBR value of 49.67%, swelling of 0.15%, and plasticity index value of 11.97%, so the soil meets the requirements to be used as pavement subgrade. Keywords: expansive soil, stabilization, road structure, subgrade, road pavement  Abstrak Tanah ekspansif memiliki potensi pengembangan dan penyusutan yang tinggi, sehingga dapat menyebabkan kerusakan struktur jalan. Oleh sebab itu, perlu dilakukan stabilisasi. Salah satu metode stabilisasi adalah menggunakan kapur dan spent catalyst dengan tujuan meningkatkan kapasitas dukung dan menurunkan swelling. Spent catalyst merupakan limbah pengolahan minyak bumi dan termasuk bahan pozzolan. Penam-bahan kapur dan spent catalyst mampu meningkatkan nilai CBR dan mereduksi swelling. Hasil studi ini menunjukkan bahwa peningkatan maksimum nilai CBR soaked maupun CBR unsoaked terjadi pada campuran tanah dengan kadar kapur optimum dan 12% spent catalyst dengan peraman 7 hari. Sedangkan campuran tanah dengan kadar kapur optimum dan 12% spent catalyst, dengan peraman 7 hari, merupakan campuran terbaik yang menghasilkan nilai CBR soaked sebesar 49,67%, swelling sebesar 0,15%, dan nilai indeks plastisitas sebesar 11,97%, sehingga tanah memenuhi syarat untuk digunakan sebagai tanah dasar perkerasan jalan. Kata-kata kunci: tanah ekspansif, stabilisasi, struktur jalan, tanah dasar, perkerasan jalan

The city ring road of Wonogiri Regency should be constructed based on a pavement design which ensure safety, convenience, but still economical. For this reason, a road pavement design method is needed to be applied in this road design process. The MDP 2017 and AASHTO 1993 road pavement design methods are methods that are often used in Indonesia to design concrete slab for pavement. This study uses both methods to determine the thickness of the concrete slab on the pavement of the Wonogiri Regency City Ring Road. The results of this study indicate that the concrete slab thickness for pavement calculated by MDP 2017 is 31 cm, while that calculated with AASHTO 1993 is 32.25 cm. The difference in the thickness of the concrete plates obtained from these two methods is relatively small. Keywords: road pavement, pavement design, concrete slab, road pavement thickness  Abstrak Jalan lingkar kota Kabupaten Wonogiri harus dibangun berdasarkan rancangan perkerasan jalan yang aman, nyaman, namun tetap ekonomis. Untuk itu, diperlukan suatu metode perancangan perkerasan jalan yang tepat untuk diterapkan pada proses perancangan jalan ini. Metode-metode perancangan perkerasan jalan MDP 2017 dan AASHTO 1993 merupakan metode-metode yang sering digunakan di Indonesia untuk perancangan tebal pelat beton untuk perkerasan jalan. Studi ini menggunakan kedua metode tersebut untuk menentukan tebal pelat beton pada perkerasan jalan lingkar kota Kabupaten Wonogiri. Hasil studi ini menunjukkan bahwa tebal pelat beton untuk perkerasan jalan yang dihitung dengan MDP 2017 adalah 31 cm, sedangkan yang dihitung dengan AASHTO 1993 adalah 32,25 cm. Beda tebal pelat beton yang diperoleh dari kedua metode ini relatif kecil. Kata-kata kunci: perkerasan jalan, perancangan perkerasan, pelat beton, tebal perkerasan jalan

Several causes can cause pavement deterioration; a weak subgrade caused one of them. If the pavement construction was built on the weak subgrade, it could damage pavement construction at the top of the subgrade. Chemical soil stabilization with cement and bitumen emulsion is one of the solutions to improve soil bearing capacity for pavement subgrade construction. The purpose of this study was to analyze the potential use of cement and bitumen emulsion as materials of chemical soil stabilization for pavement subgrade construction. In this study, soil samples were mixed by cement (3%, 6%,9%) and bitumen emulsion (3%,6%) and cured for 0, 3, and 7 days. The mixture of soil, cement, and bitumen emulsion was tested for soil bearing capacity and soil swelling by CBR and soil swelling test based on ASTM D 1883-99. Preliminary test results concluded that the original soil is included in class A-7-5 at the AASHTO classification system, and it is dominated by smectite clay minerals so that the original soil is expansive clay soil. The results of the compaction test reveal that soil stabilization with cement and bitumen emulsion can increase the mass of dry density of the soil. They reduce the optimum moisture content, where the variation of 6% cement and 3% bitumen emulsion can increase the mass of dry density by 1,340 gr / cm3 and reduce the optimum moisture content of 25%. The CBR and swelling test also disclose that soil stabilization with cement and bitumen emulsion increases soil bearing capacity and reduce swelling. The highest CBR values (soaked and unsoaked) are found in the variation of 9% cement and 3% bitumen emulsion cured by seven days, where the value is 56.9% (CBR Soaked) and 44.01% (CBR Unsoaked). The variation of 9% cement and 3% bitumen emulsion also can reduce soil swelling, where the value is 0,13%. CBR values at the variety of 9% cement and 3% bitumen emulsion cured by seven days have met the requirements of the road pavement subgrade based on SNI 03-1744-1989. Based on these tests, the cement and bitumen emulsion can use for soil stabilization material for subgrade pavement construction.

This paper describes the relationship between shareholder's political motive and corporate tax avoidance using the

In this study a software-based modeling study that can accommodate the needs to determine the surface conditions of pavement, plan for handling road damage, and predict the remaining life of pavement services. The data used in this study are primary data from the Pavement Condition Index survey on a Yogyakarta–Magelang road segment Magelang, KM 10+000-KM 11+000, and secondary data, in the form of Surface Distress Index data, International Roughness Index data, and traffic data obtained from the National Road Planning and Supervision of the Special Province of Yogyakarta. The software used in this study is Borland Delphi 7.0 software. From this study, a software called Modrova was produced. This study shows that the Modrova software is valid to use because the resulting error is relatively small. Keywords: road surface conditions, road damage, road pavement, remaining life of road pavement  Abstrak Pada studi ini dikaji suatu pemodelan berbasis perangkat lunak yang dapat mengakomodir kebutuhan untuk menentukan kondisi permukaan perkerasan jalan, merencanakan penanganan kerusakan jalan, serta mempre-diksi sisa umur layanan perkerasan jalan. Data yang digunakan pada penelitian ini adalah data primer hasil survei Pavement Condition Index pada ruas jalan Yogyakarta-Magelang, KM 10+000-KM 11+000 dan data skunder, berupa data Surface Distress Index, data International Roughness Index, serta data lalu lintas yang diperoleh dari Perencanaan dan Pengawasan Jalan Nasional Provinsi Daerah Istimewa Yogyakarta. Perangkat lunak yang digunakan pada studi ini adalah perangkat lunak Borland Delphi 7.0. Dari studi ini dihasilkan suatu perangkat lunak yang diberi nama Modrova. Studi ini menunjukkan bahwa perangkat lunak Modrova valid untuk digunakan karena kesalahan yang dihasilkan relatif kecil. Kata-kata kunci: kondisi permukaan jalan, kerusakan jalan, perkerasan jalan, sisa umur perkerasan jalan