Comparisons of Contractor and State Transportation Agency Quality Assurance Test Results on Mat Density of Hot-Mix Asphalt Concrete

Author(s):  
Rod E. Turochy ◽  
Frazier Parker
Author(s):  
Ilham I. Mohammed

Sinceasphalt concrete undergo different failure problems at different temperature and moisture conditions and for years many scientists and researchers used different kinds of materials and variety of methods for improving the properties of asphalt concrete made with either basalt or limestone.So it became necessary to provide the best possible way to get rid of these failure problems.In this study diluted zycotherm nanomaterial at three different percentages by weight of aggregate used with two aggregate types, basalt and limestone, and asphalt concrete made with the marinated aggregate and later the properties of asphalt concrete were investigated after the marination.Indirect tensile strength test and retained stability test results were used to evaluate the marinating effect.As a result zycotherm dilution by weight of aggregate has changed the properties of asphalt mixture and improved to a great extent. From the results it can be concluded that rutting and fatigue problems decreased with a great range.


Author(s):  
Kevin D. Hall ◽  
Josue Cruz ◽  
Hooi Ng

Superpave implementation has resulted in increased interest in the permeability of hot-mix asphalt concrete. Relatively open-graded Superpave mixes have given rise to concern about premature pavement failures due to increased water infiltration from the surface. Arkansas is investigating the use of a falling-head permeability test to evaluate Superpave mixes with respect to potential performance problems caused by increased permeability. The initial phase of the project concerns the development of laboratory testing procedures and equipment. Superpave field mixes from projects in Arkansas were sampled to investigate permeability testing parameters. In addition, compacted test specimens from a round-robin study of permeability were included in the testing matrix. For the Arkansas mixes, loose mix sampled at the hot-mix plant was compacted using the Superpave gyratory compactor. Field cores were also taken from completed pavement sections. Permeability tests were conducted on all samples to investigate the effect of testing time (15, 30, 45, and 60 min) and confining pressure (69 and 96.5 kPa) on the measured permeability values. Results of the testing suggest that neither the time interval used in measuring the head drop in a falling-head test nor the confining pressure used in the flexible wall testing apparatus significantly affects test results. These findings will greatly simplify testing methods and setup, making the test more attractive as a relatively routine tool for the mix design laboratory.


2007 ◽  
Vol 9 (1) ◽  
pp. 95-98 ◽  
Author(s):  
Matthew J. McGinniss ◽  
Rebecca Chen ◽  
Victoria M. Pratt ◽  
Arlene Buller ◽  
Franklin Quan ◽  
...  

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.


2016 ◽  
Vol 43 (3) ◽  
pp. 226-232 ◽  
Author(s):  
S. Pirmohammad ◽  
H. Khoramishad ◽  
M.R. Ayatollahi

In this paper, the effects of the main asphalt concrete characteristics including the binder type and the air void percentage on the cohesive zone model (CZM) parameters were studied. Experimental tests were conducted on semi-circular bend (SCB) specimens made of asphalt concrete and the fracture behavior was simulated using a proper CZM. The CZM parameters of various hot mix asphalt (HMA) mixtures were determined using the SCB experimental results. Five types of HMA mixtures were tested and modeled to consider the effects of binder type and air void percentage on the CZM parameters. The results showed that as the binder in HMA mixture softened, the cohesive energy strength increased, whereas enhancing the air void percentage led to reduction of the cohesive energy and strength values. Among the studied HMA mixtures, the highest values of CZM parameters were found for the HMA mixture containing a copolymer called styrene-butadiene-styrene.


2021 ◽  
Vol 7 (1) ◽  
pp. 66-77
Author(s):  
Ratna Yuniarti ◽  
Hasyim Hasyim ◽  
Rohani Rohani ◽  
Desi Widianty

Sifat volumetrik campuran pada laston merupakan salah satu faktor yang menentukan durabilitas (keawetan) lapis perkerasan jalan. Untuk meningkatkan keawetan lapis perkerasan jalan dan mengurangi dampak negatif terhadap lingkungan dapat dilakukan antara lain melalui modifikasi aspal dengan getah pinus dan limbah styrofoam. Tulisan ini bertujuan untuk mengkaji sifat volumetrik campuran laston menggunakan aspal modifikasi getah pinus dan limbah styrofoam tersebut. Sifat volumetrik campuran laston yang dikaji adalah rongga dalam campuran, rongga di antara mineral agregat, rongga terselimuti aspal, density dan bulk specific gravity. Pada penelitian ini digunakan agregat bergradasi rapat yang dicampur dengan aspal modifikasi pada suhu 155 oC dan dipadatkan 75 kali pada kedua sisinya. Pada seluruh benda uji, prosentase limbah styrofoam yang digunakan adalah 6% sedangkan getah pinus sebesar 0%, 1%, 2% dan 3% terhadap berat aspal modifikasi.  Hasil penelitian menunjukkan bahwa campuran laston yang menggunakan aspal modifikasi getah pinus menghasilkan nilai VFB, density dan bulk specific gravity lebih besar serta nilai VIM dan VMA lebih kecil dibandingkan dengan campuran yang menggunakan aspal modifikasi limbah styrofoam. Dengan nilai VIM dan VMA lebih kecil, campuran yang menggunakan aspal modifikasi getah pinus menghasilkan daya ikat lebih kuat sehingga memiliki durabilitas lebih tinggi. Ditinjau dari persyaratan laston sebagai lapis aus pada perkerasan jalan, penggunaan getah pinus dan limbah styrofoam sebagai modifier aspal memenuhi persyaratan volumetrik campuran. Volumetric properties of asphalt concrete is important factor to determine the durability of road pavement. Improvement the durability of road pavement and reducing negative impact of the environment can be done by using modified asphalt. This article aims to know the volumetric properties of  hot mix asphalt using pine resin and waste styrofoam as asphalt modifier. The volumetric properties include voids in mix, voids in the mineral aggregate, voids filled with bitumen, density and bulk specific gravity.  In this study, a continuously graded aggregate was used and mixed with modified asphalt at 155 oC and compacted with 75 blows on both sides. The percentage of waste styrofoam was 6% whereas the percentages of pine resin where  0%, 1%, 2% and 3% by weight of modified asphalt. From the analysis, it can be concluded that asphalt concrete containing pine resin as  modifier strengthen the binding between asphalt and agregate, due to increasing value of voids filled with bitumen (VFB), density and bulk specific gravity. Durability of asphalt concrete using pine resin as modifier was higher than that of asphalt concrete using waste styrofoam because of decreasing value of voids in mix (VIM) and voids in the mineral aggregate (VMA). Based on the specification of  asphalt concrete wearing course, the use of pine resin and waste styrofoam as asphalt modifier has fulfilled volumetric properties requirements.


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