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The assessment of the influence of styrene-butadiene-styrene copolymer on the selected rheological properties characterising durability of modified bitumens used in road pavements

Mielczarek M., Dziadosz S., Słowik M., Bilski M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2020

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Vol. 68, nr 6

1471--1479

EN

The subject matter of the research pertains to the improvement of rheological properties of petroleum bitumens by their modification with SBS (styrene-butadiene-styrene) copolymer. The authors have determined selected rheological properties characterising the durability of modified bitumens used in road pavements. The bitumens were modified in laboratory conditions with modified bitumen concentrate of a known SBS copolymer content of 9%. The result was a binder containing the known percentage of the SBS copolymer of 3%, 4.5% and 6%. Rheological properties of the tested bitumens were determined by the use of a DSR dynamic shear rheometer (in a wide temperature range from 40°C to 100°C) and a ductilometer at 5°C. DSR was used for performing MSCR test to determine the resistance of the asphalt mixture with the SBS-modified binder to permanent deformations in the high temperature range (from 40°C to 82°C). The comparison of the values of the dynamic shear modulus |G*| of all the bitumens tested shows that with a growing content of the SBS copolymer in the tested binder the value of |G*| increases, which may indicate greater resistance to permanent deformation of the asphalt pavement. The MSCR test has shown that the increased use of the SBS copolymer addition in the bitumen translates to decreasing values of the non-recoverable creep compliance Jnr. The SBS copolymer accelerates stress relaxation in the bitumen sample, thus increasing pavement resistance to low-temperature cracks. Furthermore, modification reduces the negative impact of ageing on the properties of the binder, manifested by its stiffening and slowdown of relaxation.

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Effect of Time on Dynamic Shear Modulus of Selected Cohesive Soil of One Section of Express Way No. S2 in Warsaw

Sas W., Gabryś K., Szymański A.

Acta Geophysica

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2015

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Vol. 63, no. 2

398--413

EN

Several researches published comprehensive reports on dynamic soil properties of cohesive soils, in which many of them outlined, i.e., key factors affecting the dynamic shear modulus. For cohesive soils, the modulus at small strains (γ < 10–3 %) is, first of all, a function of void ratio and effective confining stress. For clays, however, secondary time effects and clay mineralogy (fabric and structure) also appear to be important. The influence of confinement of laboratory-prepared as well as naturally deposited clays consists in an increase of shear modulus logarithmically as a function of time. In this paper, the effect of duration of the various confining pressures on dynamic shear modulus (G) of selected cohesive soils from Warsaw area was evaluated. Shear modulus was determined on the basis of resonant column tests, at low and high shearing strain amplitudes. It is shown that the calculated shear modulus is time-dependent; during approximately first 1000 minutes of consolidation, the moduli increased by almost 50%. Moreover, it is characterized by two phases: an initial one results from primary consolidation and a second one, which occurs after the end of primary consolidation, herein about 16-17 hours, and is called “long-term time effect”. This effect was found also for modulus at higher shearing strains (γ > 10–3 %, e.g., 3 × 10–3 %, 5 × 10–3 %, 8 × 10–3 %, 2 × 10–2 %).

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The Possibility of Setting Dynamic Shear Modulus Based on Multi-Channel Analysis of Surface Waves

Matula R., Czaja K., Ślusarczyk R.

Logistyka

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2014

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nr 4

4658--4664, CD6

EN

Considering logistic as a process of planning, implementing and controlling the efficient and cost-effective flow of raw materials, finished products and relevant information from point of origin to point of consumption it must be stated that effective transport is an indispensable factor that determines the process flow of goods, services, etc. Consequently, transport depends on fact how effectively net of highway is constructed, providing the best possible solution to the movement of goods and services. Design of roads and highways that are without doubt the basics of logistics activities depends on many factors, which at first glance do not have much to do with logistics in the proper sense of this word. Post designate the route of the road or highway seems to be a strategic issue both from a technical point of view as well as its subsequent exploitation. Construction of the road network in the simplest, possible way consist of building roads along as straight lines as possible. But it may be difficult to implement be-cause of many reasons. Variable environmental conditions are one of the causes that contribute to changes in the originally assumed location of the investment, which entails significant costs. Non-invasive seismic survey can be an answer for series of questions related to the stability of the ground, before the start of the investment. Results of seismic measurements can be converted to the dynamic mod-ulus of elasticity. The article presents description of possibilities of evaluation shear modulus in Holocene sediments from seismic measurements.

PL

Biorąc pod uwagę logistykę jako proces planowania, wdrażania i kontrolowania sprawnego oraz efek-tywnego przepływu surowców, wyrobów gotowych oraz odpowiedniej informacji z punktu pochodzenia do punktu konsumpcji, należy stwierdzić, że sprawny transport jest niezbędnym czynnikiem, który decyduje o płynności przepływu towarów, usług, itp. Zależy on od konstrukcji sieci dróg i autostrad, które powinny zapewniać najlepsze z możliwych rozwiązanie dla przepływu towarów i usług. Projektowanie dróg i autostrad, na których opiera się szereg działań logistycznych, zależy od wielu czynników, które na pierwszy rzut oka nie mają wiele wspólnego logistyką w ścisłym znaczeniu tego słowa. Proces wyzna-czenia trasy drogi lub autostrady wydaje się być strategicznym problemem zarówno z punktu widzenia technicznego, jak i jej późniejszego wykorzystywania. Budowa sieci dróg w najprostszy z możliwych sposobów, tzn. w postaci zbliżonej do linii prostej, może być trudne w realizacji z wielu powodów. Jedną z przyczyn są zmienne warunki naturalne, które przyczyniają się do zmian w pierwotnie założonej lokalizacji inwestycji, co pociąga za sobą znaczne koszty. Odpowiedzą na szereg pytań związanych ze stabilnością podłoża przed rozpoczęciem właściwej inwestycji mogą być badanie sejsmiczne. Wyniki tych badań mogą być przeliczone na wartości dynamicznych modułów sprężystości.