<p class="DRAbstrak">Cost estimation is the art of estimating the amount of cost required for an activity based on available information. The conceptual cost estimate is an early stage in planning a construction project. This estimate provides the cost that must be budgeted for a construction project. Cost conceptual estimates have low accuracy because the time of calculation and available information is limited. This study aims to obtain a conceptual model of the conceptual cost of short-spaced bridges. The method used is the cost index. The cost index is a figure indicating the cost per m2 of bridges at a given time. The required data are contract documents and drawings design that are built in 2012 - 2015 in Banyumas residency area. Span of bridge 4 - 38.8 meters and width of bridge 2 - 7 meters with caisson  foundation. The data were obtained from Dinas Bina Marga and Public Works Agency. The results showed that the conceptual cost model of reinforced concrete bridge with caisson foundation was BJiL = (100.540.56t2-404.528.636,58t + 406.914.286.088,58) x P x W, with t = year, P = span bridge, and W = bridge width. The error value of validation of this model is 2.31%.</p>

Highways serve nearly 80-90% of the population mobility and flow of goods. Utilization of bottom ash, a waste from coal combustion, in highway construction is one of the alternatives to reduce environmental pollution and support Clean Development Mechanism Program of Kyoto Protocol. The aim of this study is to analyze the characteristics of AC-BC mixture that uses bottom ash as partial substitute of fine aggregate and comparing with a standard mixture. Laboratory tests are performed on two different types of mixtures. The tests show that optimum asphalt content for AC-BCStandard mixture is 5.20% while AC-BCBottom Ash mixture is 5.25%. Bottom ash has higher porosity along with a little break field and has round shape so that the asphalt absorption is bigger than the crushed stone. Bottom ash can be used as an alternative aggregate to increase the value of flow of the AC-BC mixture, thus converting waste to valuable material.

Sektor konstruksi merupakan sektor yang kurang efisien dibandingkan dengan sektor manufaktur dan lainya. Ditandai dengan produktifitas rendah, kualitas rendah dan limbah (waste) berupa waktu dan material. Teknologi konstruksi merupakan salah satu metode konstruksi untuk meningkatkan produktifitas. Pelaku konstruksi dituntut untuk menyelesaikan proyek dengan waktu singkat dan hasil yang optimal. Salah satu cara yang dilakukan untuk meningkatkan efektivitas kinerja adalah menerapkan metode Building Information Modeling (BIM) pada pekerjaan perhitungan kuantitas agar dapat meningkatkan efektivitas kerja. Penelitian ini bertujuan untuk mengetahui peningkatan efektivitas kerja dengan penerapan konsep BIM dibandingkan dengan metode konvensional dalam menghitung kuantitas kegiatan. Obyek penelitian adalah Gedung Pelayanan Pendidikan Fisip Universitas Jenderal Soedirman Purwokerto. Pada proses penyelesaian proyek, perhitungan kuantitas material dilakukan secara manual dari detailed engineering design (DED), selanjutnya  elemen struktur dimodelkan kembali ke gambar tiga demensi dan perhitungan kuantitas dengan sofware Revit. Dari penilitian yang dilakukan didapatkan efisiensi volume beton terbesar terdapat pada struktur balok dan terkecil berada pada struktur kolom. Lalu efisiensi volume besi dan bekisting terbesar terdapat pada struktur balok dan terkecil terdapat pada struktur plat lantai.

Abstract. Road conditions are frequently subjected to damage that outlasts the road's design life. One of these is due to the material's mechanical capability, which is insufficient to withstand traffic loads and weather conditions. The incorporation of plastic and tire waste into Hot Mix Asphalt is one of the efforts to improve the material's mechanical quality (HMA). In addition to reducing the asphalt concentration in the mixture, the percentage of plastic and tire debris reduces the environmental impact. The use of plastic and tire waste in HMA can aid in the creation of green roads. The goal of this research is to see how plastic and tire waste affect HMA performance in Marshall testing. The research was conducted by making test samples with variations of waste materials percentage. Then, the Marshall test was carried out. Analysis of test results includes volumetric properties and Marshall characteristics. The test results showed that the addition of plastic and tire waste was able to improve the performance of the HMA mixture. However, the performance of the HMA mixture will decrease due to the influence of water soaking the HMA mixture. The addition of the optimum waste was obtained by 2.5% at the optimum asphalt content of 5.5%.