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1

Effects of zeolites and hydrated lime on volumetrics and moisture resistance of foamed warm mix asphalt concrete

Chomicz-Kowalska Anna, Maciejewski Krzysztof, Iwański Mateusz Marek, Janus Karolina

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 2

art. no. e136731

EN

The paper concerns the utilization of hydrated lime and zeolites as additives in warm mix asphalt produced with foamed bitumen. The mentioned additives were added to the mixtures in exchange for specific quantities of mineral filler, which amounted to 0.4% and 1.2% of hydrated lime or 0.4% of water-modified and 1.0% of air-dry zeolites in mineral mix. The study investigated warm-produced mixtures with 4.5% and 4.8% binder content and production and compaction temperatures set at 120⁰C and 100⁰C respectively. Additionally, reference hot and warm mixtures were evaluated. The testing included: air void content, indirect tensile strength in dry state and after one freeze-thaw cycle as well as the resulting resistance to moisture and frost damage index. The mixtures incorporating hydrated lime and lower bitumen content of 4.5% exhibited increased air voids and mostly unchanged mechanical performance when compared to the reference warm mix. Increased bitumen content has resulted in significantly improved performance in moisture resistance and compactability which could be compared to that of the reference hot-produced mixture. On the other hand, the incorporation of zeolites in the foamed bitumen mixtures resulted in all cases in increased air void content in the samples. This has apparently led to decreased indirect tensile strength, in both the dry state and after the freeze-thaw cycle. Based on the results it was concluded that the production temperature of the zeolite-bearing mixtures was too low for the zeolite water to significantly improve the mix’ workability and therefore positively affect its mechanical parameters.

2

The effect of WMA additive on basic properties of 35/50 and 50/70 foamed road bitumen

Chomicz-Kowalska Anna, Bartos Joanna, Maciejewski Krzysztof, Remisova Eva, Komacka Jozef, Holy Michal

Structure and Environment

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2019

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Vol. 11, no. 2

126--138

PL

The need to use asphalt additives along with the reduction in the temperatures of asphalt mixes results mainly from the need to ensure the durability of asphalt pavements. The use of foamed asphalt for warm mix asphalt (WMA) enables reducing the temperatures of asphalt mixes by approx. 30-40°C in relation to traditional hot mix asphalt. The article presents an analysis of the impact of a liquid chemical additive that is currently used in the WMA technology on changes in foamed asphalt properties. The assessment embraced the basic features of bitumens and the parameters of the asphalt foam manufactured based on them. The base bitumen used in the testing included road asphalt 35/50 and 50/70, whereas the modification of their properties was carried out using the WMA additive content of 0.3% to 0.6% in relation to the asphalt mass. The asphalt foam parameters were measured after foaming at 155°C and with the foaming water content (FWC) of 1.5% to 3.5% with increments of 1.0%.

EN

Potrzeba stosowania dodatków do asfaltu wraz z obniżaniem temperatur technologicznych mieszanek mineralno-asfaltowych wynika głównie z konieczności zapewnienia trwałości nawierzchni asfaltowej. Stosowanie asfaltu spienionego do technologii na ciepło (WMA) umożliwia obniżenie temperatur mieszanek mineralno-asfaltowych o około 30-40ºC względem tradycyjnej technologii na gorąco. W artykule przedstawiono analizę wpływu dodatku chemicznego w postaci płynnej, który stosowany jest obecnie do technologii WMA, na zmiany właściwości asfaltów spienionych. Ocenie poddano podstawowe cechy lepiszczy oraz parametry wyprodukowanej na ich bazie piany asfaltowej. W badaniach jako bazowe lepiszcze zastosowano asfalty drogowe 35/50 oraz 50/70, natomiast do modyfikacji ich właściwości zastosowano dodatek WMA w ilości od 0,3% do 0,6% w stosunku do masy asfaltu. Pomiar parametrów piany asfaltowej przeprowadzono przy temperaturze wyjściowej asfaltu (przed spienieniem) wynoszącej 155ºC oraz przy zawartości wody spieniającej (FWC - Foaming Water Content) w zakresie od 1,5% do 3,5% ze wzrostem co 1,0%.

3

Kierunki rozwoju nawierzchni asfaltowych

Błażejowski K., Wójcik-Wiśniewska M.

Materiały Budowlane

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2017

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nr 4

77--79

4

Laboratory testing of low temperature asphalt concrete produced in foamed bitumen technology with fiber reinforcement

Chomicz-Kowalska A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 6

779--790

EN

The paper presents the design process and test results of warm mix asphalt concrete produced with modified foamed bitumen and recycled synthetic fiber reinforcement. Recycling and low-temperature asphalt production techniques are now seen as the possibilities to increase the sustainability and energy effectiveness of road construction. Although low processing temperatures permit increased use of reclaimed and recycled materials in new asphalt mixes, they sometimes result in impaired service performance. The aim of this article was to present a possibility of producing a better performing asphalt concrete (in comparison to a control hot-mix) at lower temperatures. For this purpose two road paving bitumens modified with a surface active agent and a Fischer-Tropsch wax thoroughly tested for their basic, rheological characteristics and foaming performance. Selected binders were used for producing two control mixes (hot-mix and foamed warm mix with 35/50 bitumen) as well as the experimental mix with the modified 50/70 bitumen and an addition of synthetic fiber material from recycling of automotive tires. Basic properties of the mixes were tested (air void content, moisture susceptibility with one freeze-thaw cycle, wheel tracking) along with stiffness moduli and fatigue resistance. It was concluded that the control foamed warm-mix performed significantly worse than the hot-mix, while the experimental warm-mix with modified bitumen and fiber additive exhibited increased performance and resistance to fatigue and moisture.

5

The extended assessment of warm mix asphalts durability

Bańkowski W., Horodecka R., Gajewski M., Mirski K.

Roads and Bridges - Drogi i Mosty

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2016

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Vol. 15, no. 2

157--173

EN

The present paper outlines the results of tests performed on bituminous mixtures made by applying WMA, typical and modified bitumens. The mixtures AC 16 and SMA 8 were tested in respect to the compactibility (in a gyratory press and PBS cylinder compactor), water resistance, fatigue resistance, resistance to low-temperature cracking (through the TSRST method), complex modulus in a broad scope of frequencies, and crack propagation in the SCB apparatus. The impact of the technological and long-term ageing was taken into account. All tests were performed on the reference specimens and the specimens with WMA bitumens compacted at the temperature lower than the standard compaction temperature for a given mixture by 20°C and 40°C respectively. It has been proved that reducing the compaction temperature by 20°C is possible without deteriorating the mixture parameters. Moreover, in case of reducing that temperature by 40°C the majority of requirements have been met as well. The tests have confirmed in broad scope good functional characteristics of warm mix asphalts.

PL

W pracy przedstawiano wyniki badań przeprowadzonych na mieszankach mineralno-asfaltowych wykonanych z zastosowaniem asfaltów WMA oraz standardowych asfaltów drogowych i modyfikowanych. Na mieszankach AC 16 i SMA 8 przeprowadzono badania zagęszczalności (w prasie żyratorowej i zagęszczarce walcowej PBS), wodoodporności, odporności na zmęczenie, odporności na pękanie niskotemperaturowe (metodą TSRST), badania modułu zespolonego w szerokim zakresie częstotliwości oraz odporności na propagację pęknięcia w aparacie SCB. Uwzględniono również wpływ starzenia technologicznego i eksploatacyjnego. Wszystkie badania zostały przeprowadzone na próbkach referencyjnych oraz próbkach z asfaltami WMA, które zagęszczano w temperaturze niższej odpowiednio o 20°C i 40°C od standardowej temperatury zagęszczania dla danej mieszanki. Wykazano, że jest możliwe obniżenie temperatury zagęszczania o 20°C bez obniżenia parametrów mieszanki, a w przypadku obniżenia temperatury o 40°C również większość wymagań została spełniona. Przeprowadzone badania potwierdziły w szerokim zakresie dobre właściwości funkcjonalne mieszanek na ciepło.

6

Influence of hydrated lime on the properties of filler-bitumen composite

Iwański M. M., Maciejewski K., Ramiączek P.

Structure and Environment

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2015

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Vol. 7, no. 2

55--60

EN

To guarantee the quality of warm mix asphalt, one of the prerequisites is to provide adequate adhesion between the bituminous binder and the aggregates. To achieve this goal, filler-bitumen mixes were examined with a replacement of mineral filler with hydrated lime in amounts of 0%, 10%, 20%, 30% and 40%. A 35/50 bitumen was used as a binder in the filler-bitumen mix in amounts of 4.8%, 5.1%, 5.4% and 5.8%. The assessed properties of filler-bitumen composite comprised: penetration, softening point and Fraass breaking point. The influence of the hydrated lime on the properties of the filler-bitumen compound was found to be significant and beneficial.

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Właściwości asfaltu z dodatkami modyfikującymi po procesie starzenia krótkoterminowego

Iwański M., Cholewińska M., Mazurek G.

Budownictwo i Architektura

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2014

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Vol. 13, nr 1

15--27

PL

Celem badań była analiza porównawcza wpływu nowoczesnych modyfikatorów (Trynidad, Glisonit, wosk syntetyczny, środek adhezyjny) przeznaczonych potencjalnie do produkcji mieszanek mineralno-asfaltowych w obniżonej temperaturze. Jako lepiszcze referencyjne wykorzystano asfalt o penetracji 35/50. Wpływ wykorzystanych modyfikatorów na właściwości asfaltu oceniono poprzez oznaczenie takich właściwości jak: penetracja, temperatura mięknienia oraz temperatura łamliwości. Oznaczenia powyższych właściwości zostały przeprowadzone przed i po procesie starzenia krótkoterminowego symulowanego metodą RTFOT. Modyfikatory dozowano w pięciu wariantach w stosunku do masy asfaltu referencyjnego. Modyfikacja asfaltu woskiem syntetycznym spowodowała wzrost zakresu plastyczności, podczas gdy zastosowanie modyfikatora obniżającego napięcie powierzchniowe nie wywołało znacznych zmian w odniesieniu do właściwości asfaltu. Również proces starzenia krótkoterminowego istotnie wpłynął na wartości oznaczonych cech asfaltu. Najwyższe tempo zmian po procesie starzenia krótkoterminowego zanotowano w przypadku zastosowania asfaltów naturalnych. Wykazane badania pozwoliły stwierdzić, że najkorzystniejszym modyfikatorem asfaltu 35/50 jest wosk syntetyczny oraz środek adhezyjny. Należy się spodziewać, że pozwalają one zapewnić trwałość mieszanki mineralno asfaltowej wytwarzanej w obniżonej temperaturze.

EN

The aim of the study was a comparative feasibility studies of the influence of modern modifiers (Trinidad , Gilsonit , synthetic wax , adhesive agent ) for incorporating them to the bituminous mixture at low temperatures production. The bitumen of penetration grade 35/50 was used as reference binder. The effect of modifiers on bitumen behaviour was assessed by means of followed properties: penetration grade, softening point temperature and the breaking point temperatures. Measurements of the above properties have been carried out before and after simulated aging according to RTFOT. Modifiers were dosed in five variants to bitumen by weight. Modification of bitumen with synthetic wax increased the level of bitumen stiffness while the use of the fatty amine did not invoke significant changes in bitumen properties (regarding neat bitumen). Short-term aging significantly influenced on characteristics of bitumen, as well. The highest bitumen change rate after aging was observed in the case of the use of natural bitumen. It was found that the most preferred modifiers to paving bitumen 35/50 were a synthetic wax and a adhesive agent. It is expected that they allow to ensure the durability of bituminous mixtures produced at reduced temperatures.

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Influence of synthetic fibres on the properties of asphalt concrete produced at reduced temperature

Iwański M. M., Chomicz-Kowalska A.

Structure and Environment

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2013

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Vol. 5, no. 3

21--29

EN

This paper presents the effects of synthetic fibers from car tire recycling on the properties of binder course asphalt concrete. The asphalt concrete was produced in conventional hot mix asphalt technology as well as in lowered temperatures as warm mix (WMA) and half-warm mix asphalt (HWMA). The aim of the research was to analyze the influence of fiber content and the production technique on the air void content, moisture resistance (ITSR), resistance to permanent deformation (WTS AIR), stiffness modulus at 20°C and fatigue resistance under indirect tension test. The performed analyses have proven the influence of synthetic fibers on the characteristics of asphalt concrete produced in WMA technology (with synthetic F-T wax modified bitumen) and HWMA technology (with foamed bitumen) to be significant.