Determination of viscoelastic properties from the indirect tensile stiffness modulus (ITSM) test

Author(s):  
A. C. Collop
Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4731
Author(s):  
Mateusz M. Iwański

Half-warm mix asphalt (HWMA) mixtures can be produced at temperatures ranging from 100 °C to 130 °C, depending on the production methods used. The lowest mixing temperature can be achieved by using water-foamed bitumen. The mixture should be characterized by a long service life, defined by the resistance to permanent deformation and high stiffness modulus at temperatures above zero. It is therefore important to ensure the adequately high quality of the bitumen binder. Bitumen 50/70 was provided with appropriate quality foaming characteristics (expansion ratio, ER, half-life, t1/2) by adding a surface-active agent (SAA) at 0.6 wt % before foaming. Then asphalt concrete (AC) 8 S was designed and produced with the recommended water-foamed binder. Hydrated lime, an additive substantially affecting asphalt concrete mechanical parameters, was used at 0, 15, 30, and 45 wt % as a partial replacement for the limestone filler. The influence of the amount of hydrated lime on the content of voids, indirect tensile stiffness modulus at −10 °C, 0 °C, +10 °C, +20 °C, and +30 °C, and the resistance to permanent deformation was investigated. Statistical analysis of the test results showed the quantity of 30% to be the optimum hydrated lime content. The AC 8 S resistance to permanent deformation was determined at the optimum hydrated lime content. The comprehensive evaluation revealed a synergistic effect between bitumen 50/70, modified before foaming with 0.6 wt % SAA and 30 wt % hydrated lime as the limestone filler replacement, and the half warm mixture AC 8 S, in terms of the standard requirements and durability of the HWMA concrete in pavement applications.


Author(s):  
Hicham Mezouara ◽  
Latifa Dlimi ◽  
Abdelouahhab Salih ◽  
Mohamed Afechcar ◽  
Houcine Zniker

This study treats the measurement uncertainties that we can find in the stiffness modulus of the bituminous test. We present all the sensors installed on rigidity modulus measurement chains and also their uncertainty ranges. Several parameters influence the rigidity module's value, such as the parameters related to experimental conditions, and others are rather connected to the equipment's specification, which are the speed, the loading level, the temperature, the tested sample dimension, and the data acquisition, etc. All these factors have a great influence on the value of the modulus of rigidity. To qualify the uncertainty factors, we used two approaches: the first one is made by following the method described by the GUM (Guide to the expression of uncertainty in measurement), the second approach based on the numerical simulation of the Monte Carlo. The two results are then compared for an interval of confidence of 95%. The paper also shows the employment of the basic methods of statistical analysis, such as the Comparing of two variances. Essential concepts in measurement uncertainty have been compiled and the determination of the stiffness module parameters are discussed. It has been demonstrated that the biggest source of error in the stiffness modulus measuring process is the repeatability has a contribution of around 45.23%.


2019 ◽  
Vol 7 (4) ◽  
Author(s):  
Maulana Andhika Pratama Ilyas ◽  
Ary Setyawan ◽  
Djumari Djumari

<p>Penggunaan lapis tipis campuran aspal panas (<em>Thin Surfacing Hot Mix Asphalt</em>) merupakan salah satu alternatif yang dapat mengantisipasi masalah ketebalan perkerasan jalan. <em>Crumb rubber (CR) </em>merupakan limbah hasil dari vulkanisir ban yang merupakan masalah serius bagi lingkungan dan penggunaan <em>crumb rubber </em>lebih murah daripada karet alam atau jenis-jenis polymer yang lain. Tujuan dari penelitian ini adalah untuk mengkaji kadar aspal optimum pada <em>Thin Surfacing Hot Mix Asphalt </em>dengan penambahan <em>crumb rubber </em>dan tanpa penambahan <em>crumb rubber</em> serta membandingkan pengaruh penambahan <em>crumb rubber</em> terhadap karakteristik <em>stiffness modulus</em> pada masing masing campuran. Dengan metode eksperimental menggunakan metode <em>Marshall </em>dapat ditentukan nilai stabilitas untuk mengetahui kadar aspal optimum masing masing campuran yang akan dilaksanakan di Laboratorium Jalan Raya Universitas Sebelas Maret Surakarta. Selanjutnya, metode <em>Indirect Tensile Stiffness Modulus</em> dapat digunakan untuk menentukan besarnya <em>stiffness modulus</em> akan dilaksanakan di Laboratorium Perkerasan Jalan Pusjatan Kementerian Pekerjaan Umum dan Perumahan Rakyat di Bandung serta di Laboratorium Jalan Raya Universitas Udayana Bali. Aspal yang digunakan adalah aspal penetrasi 60/70 dengan penambahan crumb rubber sebesar 0%, 0,5%, 1,0% dan 1,5% dari berat total campuran. Dari hasil <em>marshall test</em> diperoleh kadar aspal optimum yaitu untuk masing-masing kadar <em>crumb rubber</em> 0%, 0,5%, 1,0% dan 1,5% yaitu 5,41%, 5,50%, 5,39% dan 5,52%. <em>Thin Surfacing Hot Mix Asphalt</em> dengan penambahan <em>Crumb Rubber</em> 1% menurunkan nilai Kadar Aspal Optimum sebesar 0,4% dan meningkatkan nilai stabilitas sebesar 2% dibandingkan dengan <em>Thin Surfacing Hot Mix Asphalt</em> tanpa penambahan <em>Crumb Rubber</em> 1%. Sedangkan untuk uji ITSM dari <em>Thin Surfacing Hot Mix Asphalt</em> dengan penambahan <em>Crumb Rubber</em> 1% menurunkan nilai <em>Stiffness Modulus</em> sebesar 51,3% untuk suhu 20°C, dan meningkatkan nilai <em>Stiffness Modulus</em> sebesar 30,7% untuk suhu 40°C<em>. </em>Selain itu, <em>Thin Surfacing Hot Mix Asphalt</em> dengan penambahan <em>Crumb Rubber </em>1% mempunyai ketahanan terhadap suhu lebih besar yaitu hanya 75% penurunan nilai <em>stiffness modulus</em> dari suhu 20°C ke suhu 40°C dibandingkan dengan <em>Thin Surfacing Hot Mix Asphalt</em> tanpa penambahan <em>Crumb Rubber</em> 1% yaitu<em> </em>sebesar 91%<em>.</em></p>


2018 ◽  
pp. 44-47
Author(s):  
F.J. Тurayev

In this paper, mathematical model of nonlinear vibration problems with fluid flows through pipelines have been developed. Using the Bubnov–Galerkin method for the boundary conditions, the resulting nonlinear integro-differential equations with partial derivatives are reduced to solving systems of nonlinear ordinary integro-differential equations with both constant and variable coefficients as functions of time.A system of algebraic equations is obtained according to numerical method for the unknowns. The influence of the singularity of heredity kernels on the vibrations of structures possessing viscoelastic properties is numerically investigated.It was found that the determination of the effect of viscoelastic properties of the construction material on vibrations of the pipeline with a flowing liquid requires applying weakly singular hereditary kernels with an Abel type singularity.


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