Ludfi Djakfar

THE EFFECT OF LIMESTONE AND REHEATING TEMPERATURE ON COLD PAVING HOT MIX ASPHALT

The objective of the study is to evaluate the effect of the limestone proportion and reheating temperature to the Marshall characteristics of the cold paving hot mix asphalt (CPHMA) using a natural asphalt from Buton, Indonesia. The mix is prepared and mixed in hot temperature like hot mix asphalt, but laid and compacted at normal temperature. The normal application of this mix is for patchwork, due to its lower performance. In order to upgrade its performance, the research attempts to add limestone material and reheat the mix before laying and compacting. As many as 60 Marshall specimens were prepared with varied asphalt content, percentage of limestone, and reheating temperatures. The specimen were prepared in two stages: mixing process and compaction process. The mixing process was performed like regular hot mix asphalt. After the mixing, the specimens were placed in a batch for 24 hours. The mixes were then placed in the Marshall tube to prepare the Marshall specimens, compacted, and tested. The results showed that heating the mix to about 42 o C significantly improves the mix performance, particularly on its Marshall stability. The existence of limestone in the mix also improved its performance. Based on the results it can be concluded that given some treatments, the CPHMA can be used not only as patching material but also as structural layer material, particularly for low to medium traffic rural road.

GRADATION BAND OF SOME TYPES MATERIAL FOR RESERVOIR BASE OF POROUS PAVEMENT

Recent year, reducing of open area and the extreme rainfall are reason for the flood in some city in Indonesia. The drainage and infiltrated well were constructed in some parts of the city could not solve the problem yet. The porous pavement can be applied to reduce run off, rate and pollutants. Reservoir base or sub base is an important layer as part of structure and also temporary store rainfall water before infiltrate to the subgrade. This study assessed characteristic and gradation some types of materials as stone crush, limestone and steel slag for porous pavement and evaluate this performance based on California Bearing Ratio (CBR) and porosity. Naturally these characteristics are contrary, in which for high porosity materials will have low bearing capacity. There are 7 gradations consist of 4 gradations in coarse aggregate and 3 gradations based on Bina Marga (Indonesian Highway Agency). The result showed that CBR of stone crush is high in uniform course material gradation than limestone and steel slag. In the term of porosity, the result completely the same for all materials in which the uniform gradation give the high porosity. It makes sign the influence of hardness and gradation of material will give contribution for bearing capacity and only gradation influence to porosity. The material are suitable for reservoir layer of porous pavement for light traffic load. Gradation band is lied between Bina Marga and NAPA and AASHTO specification.

Performance of Recycled Porous Hot Mix Asphalt with Gilsonite Additive

The objective of the study is to evaluate the performance of porous asphalt using waste recycled concrete material and explore the effect of adding Gilsonite to the mixture. As many as 90 Marshall specimens were prepared with varied asphalt content, percentage of Gilsonite as an additive, and proportioned recycled and virgin coarse aggregate. The test includes permeability capability and Marshall characteristics. The results showed that recycled concrete materials seem to have a potential use as aggregate in the hot mix asphalt, particularly on porous hot mix asphalt. Adding Gilsonite at ranges 8–10% improves the Marshall characteristic of the mix, particularly its stability, without decreasing significantly the permeability capability of the mix. The use of recycled materials tends to increase the asphalt content of the mix at about 1 to 2% higher. With stability reaching 750 kg, the hot mix recycled porous asphalt may be suitable for use in the local roads with medium vehicle load.

Pengaruh Penambahan Serbuk Kayu Jati Terhadap Karakteristik Marshall Pada Campuran Aspal Porus

Aspal merupakan material yang digunakan pada pekerjaan perkerasan lentur jalan. Genangan air yang sering terjadi terutama setelah hujan bisa menjadi masalah terhadap ketahanan aspal. Salah satu alternatif yang dapat digunakan untuk mencegah permasalahan ini adalah penggunaan aspal porus untuk digunakan dalam pekerjaan perkerasan jalan. Aspal porus adalah campuran yang memiliki gradasi agregat kasar lebih banyak dibandingkan dengan agregat halus. Penelitian ini membahas mengenai pengaruh penambahan serbuk kayu jati terhadap nilai Marshall yang ada pada campuran aspal porus. Penggunaan serbuk kayu jati ini juga dapat mengurangi jumlah limbah serbuk kayu yang ada. Variasi yang dilakukan pada penelitian ini adalah variasi kadar serbuk kayu jati dan variasi suhu perendaman. Variasi kadar serbuk kayu jati sebesar 4%, 5% dan 6% sedangkan variasi suhu perendaman 45oC, 60oC dan 75oC. Jumlah benda uji untuk mencari KAO yang dibuat sebanyak 9 buah benda uji. Benda uji Marshall Immersion sebanyak 9 buah benda uji. Penelitian ini menggunakan metode analisis ANOVA Dua Arah. Hasil uji statistik menunjukan bahwa tidak ada pengaruh dari penambahan serbuk kayu jati terhadap nilai Marshall pada campuran aspal porus.