Wodoodporność recyklowanej podbudowy z asfaltem spienionym w aspekcie składu spoiwa drogowego

The paper describes research results of recycled base which was performedin a cold deep recycling technology with foamed bitumen and different type of hydraulicmixed binder in the aspect of water resistance. An individual design of a composition of abinder enables to achieve a precise adjustment of a binder’s impact to local conditions andrequired parameters of a recycled base. The design a recycled base with foamed bitumensimulated a cold deep recycling process with materials from existing crushed bituminouspavement layers ("technology in-situ"). To produce the foamed bitumen a road bitumen ofpenetration grade 50/70 was used. Moreover, the following mineral components werecategorised as a waste material: reclaimed asphalt pavement, 0/31,5 mm aggregate andaggregates for soil gradation improvement 0/4. A composition of the recycled base consisted of the binders prepared in the laboratory as a result of a mix of three basic components.The percentage of individual road binders was determined in line with the plan of thesimlex-centroid experiment. For the purpose of determining an influence of such a hydraulicroad binder on the water resistance in recycled base, the following tests were carried out:void contents Vm, tensile strength ratio TSR (water resistance). Additionally, an evaluationof increase of indirect tensile modulus (IT-CY) was conducted. On the basis of the testresults, a varied impacts of tested hydraulic road binders on mechanical properties andwater resistence of recycled base with foamed bitumen were observed. On the basis of theplan of the experiment, it was possible to determine the recommended road binder composition that enabled to obtain the water resistance in the recycled base with foamed bitumenW referacie przedstawiono rezultaty badań recyklowanej podbudowywykonanej w technologii recyklingu głębokiego na zimno z asfaltem spienionym orazspoiwem mieszanym. W badaniach szczególną uwagę zwrócono na jej wodoodporność.Indywidualne projektowanie składu spoiwa pozwala na precyzyjne dostosowanie jegooddziaływania do warunków terenowych oraz wymaganych parametrów recyklowanejpodbudowy. Projekt recyklowanej podbudowy z asfaltem spienionym symulował procesrecyklingu głębokiego na zimno. Zastosowane składniki mineralne tj. destrukt asfaltowy,kruszywo 0/31,5 mm oraz kruszywo doziarniające 0/4 stanowiły materiał odpadowyz istniejącej konstrukcji. W składzie recyklowanej podbudowy zastosowano spoiwa drogowe, które wytworzono w warunkach laboratoryjnych z wymieszania trzech bazowychskładników. Udział procentowy poszczególnych spoiw drogowych określono zgodnychz planem eksperymentu sympleksowo-centroidowego. Na podstawie uzyskanych wynikówbadań stwierdzono różnorodny wpływ analizowanych składników spoiw drogowych nawłaściwości mechaniczne oraz wodoodporność recyklowanej podbudowy. W oparciuo zastosowany plan eksperymentu możliwe było określenie składu spoiwa drogowego, którezapewni uzyskanie recyklowanej podbudowy odpornej na działanie wody

Characteristics of the complex modulus of recycled cold mix with foamed bitumen and recycled concrete aggregate

This article presents research on recycled cold mix with foamed bitumen (MCAS) containing recycled concrete aggregate. The primary concept driving this research was to determine if recycled concrete aggregate (RC) could be used as a substitute for reclaimed asphalt pavement (RAP). Recycled concrete aggregate was used in the MCAS mix in amounts ranging from 20%, 60% and 80%. The reference mix was the MCAS mix containing 50% reclaimed asphalt pavement (RAP) and virgin aggregate. Identical 0/31.5-mm continuously graded dolomite virgin aggregate was used in all mixes. 2.5% foamed bitumen (FB) and 2.0% CEM I 42.5R Portland cement (PC) were used to increase the cohesion of the mineral mix. Foamed bitumen was produced from 50/70 penetration paving bitumen. The behaviour of the recycled base course was tested in the range of cyclic sinusoidal strain with amplitude εo = 25–50 με. The tests were carried out in the (-7°C, 5°C, 13°C, 25°C, 40°C) temperature and (0.1 Hz, 0.3 Hz, 1 Hz, 3 Hz, 10 Hz, 20 Hz) loading time range. The complex modulus was tested in a direct tension-compression test on cylindrical samples (DTC-CY) in accordance with EN 12697-26. The results of the tests were used to assess the complex modulus (E*), phase angle (φ) and complex modulus components (E1) and (E2).Tests of the mixes indicate that recycled concrete aggregate can be used in recycled cold mixes in amounts of up to 80%. Increasing the amount of recycled concrete aggregate does not cause excessive stiffness of the recycled mix in comparison with the reference mix. The tests did not demonstrate a significant difference in terms of the phase angle (φ), which indicates a similar content of the viscous part and elastic part in the obtained complex modulus for the reference mix (RAP + MCAS) and the mix containing recycled concrete aggregate (RC + MCAS)

Wpływ laboratoryjnych metod zagęszczania na właściwości fizykomechaniczne recyklowanych mieszanek mineralno-asfaltowych z asfaltem spienionym

This study attempts to evaluate the influence of two advisable methods for compacting laboratory specimens of road base recycled mixes with foamed bitumen (MCAS) and bitumen emulsion (MCE). The obligatory regulations for this technology permit fabrication of the specimens using either an impact Marshall compactor or a static hydraulic press. The research showed that the compaction method influenced both the physical and mechanical properties of samples regardless of the type of bitumen binder. What is more, the structure of the material changed after the impact compaction process, which manifested in fact that many of the aggregate particles were crushed in its course. Better strength and resistance to moisture damage was observed in samples prepared in the hydraulic press. This was associated with lower void contents obtained in this compaction method.W referacie przedstawiono wyniki badań oceny wpływu laboratoryjnych metod zagęszczania na właściwości recyklowanych mieszanek z asfaltem spienionym (MCAS) oraz z emulsją asfaltową (MCE). Obecne wymagania opracowane i stosowane w naszym kraju przy realizacji zadań drogowych na etapie projektowania składu mieszanek oraz kontroli właściwości wykonywanej warstwy podbudowy w technologii recyklingu na zimno dopuszczają dwie metody formowania prób w warunkach laboratoryjnych: zagęszczanie statyczne prasą hydrauliczną oraz udarowe w ubijaku Marshalla. Na podstawie badań stwierdzono, iż rodzaj metody zagęszczania ma wpływ na cechy fizyczne i mechaniczne recyklowanych mieszanek. Zaobserwowano również, że sposób formowania prób wpływa na strukturę uzyskanego materiału, gdzie znaczny udział ziaren materiału mineralnego uległ rozkruszeniu podczas zagęszczania udarowego. Próbki zagęszczane w sposób statyczny uzyskały lepsze parametry wytrzymałościowe oraz charakteryzowały się wyższą odpornością na działanie wody, co ma związek z niższą zawartością wolnych przestrzeni uzyskiwaną w próbkach zagęszczanych tą metodą

Właściwości asfaltu z dodatkami modyfikującymi po procesie starzenia krótkoterminowego

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.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

Stiffness Evaluation of Laboratory and Plant Produced Foamed Bitumen Warm Asphalt Mixtures with Fiber Reinforcement and Bio-Flux Additive

The present paper investigates the viscoelastic stress-strain responses of laboratory and plant produced warm mix asphalt mixtures containing basalt fiber dispersed reinforcement. The investigated processes and mixture components were evaluated for their efficacy in producing highly performing asphalt mixtures with decreased mixing and compaction temperatures. Surface course asphalt concrete (AC-S 11 mm) and high modulus asphalt concrete (HMAC 22 mm) conventionally and using a warm mix asphalt technique with foamed bitumen and a bio-derived fluxing additive. The warm mixtures included lowered production temperature (by 10 °C) and lowered compaction temperatures (by 15 °C and 30 °C). The complex stiffness moduli of the mixtures were assessed under cyclic loading tests at combinations of four temperatures and five loading frequencies. It was found that the warm produced mixtures were characterized by lower dynamic moduli than the reference mixtures in the whole spectrum of loading conditions, however, the mixtures compacted at the 30 °C lower temperature performed better than the mixtures compacted at 15 °C lower temperature, specifically when highest testing temperatures are considered. The differences in the performance of plant and laboratory produced mixtures were ascertained to be nonsignificant. It was concluded that the differences in stiffness of hot mix and warm mixtures can be attributed to the inherent properties of foamed bitumen mixtures and that these differences should shrink in time

Effects of the Water-Based Foaming Process on the Basic and Rheological Properties of Bitumen 70/100

The process of water-based foaming of bitumen produces binders that can be incorporated in cold recycled asphalt mixes and pavement upper structural layers made of half-warm mix asphalt prepared at 100–130 °C. During the foaming process, cold water and air act on hot bitumen (160–170 °C), which results in the explosive vaporization of water leading to changes in the binder structure. The impact of foaming on the properties of bitumen 70/100 was evaluated by investigating the binder characteristics before and after foaming. Determination of two foaming parameters, maximum expansion and half-life, was followed by measurements of penetration at 25 °C, softening point, Fraass breaking point, and dynamic viscosity at 60, 90, and 135 °C. Rheological and low-temperature tests were also performed before and after foaming bitumen 70/100. The Bending Beam Rheometer method was applied to determine the low temperature stiffness modulus. A DHR-2 rheometer was used to determine the dynamic modulus and phase angle of the tested binder. The Black and master curves before and after foaming were plotted in the 2S2P1D model and the model parameters were analysed. Analysis of the test results confirmed the effects of the foaming process on the basic, low-temperature, and rheological characteristics of the bitumen

Multidimensional Analysis of the Effects of Waste Materials on Physical and Mechanical Properties of Recycled Mixtures with Foamed Bitumen

The paper reports the results from the tests of recycled mixture samples containing waste materials. Six types of waste materials were used in the mineral mix, in various configurations. Statistical inference was based on the multidimensional analysis through the reduction of input data size. Three groups of recycled mixtures were identified, each representing significantly different properties. The first group included rigid recycled mixtures, the second group comprised flexible mixtures, and those with the lowest cohesion and rigidity were in the third group. The statistical inference demonstrated that the recycled mixtures with waste materials to be most recommended were those with a high bitumen content (>2.5%). A high proportion of reclaimed asphalt pavement material was found to provide high performance of the recycled mixture, whereas recycled aggregate reduced the stiffness of the mix and its resistance to moisture

Rheological Properties of the Bituminous Binder Extracted From SMA Pavement with Hydrated Lime

The durability of pavement layers depends on the type of bitumen and changes in its material structure during service life. In 1999, while rebuilding and modernizing road infrastructure in Kielce (Poland), a stone mastic asphalt wearing coarse layer with hydrated lime was placed on one of the town’s main streets. Stone mastic asphalt mixture contained 6.2% of D70 bitumen (currently 50/70) and 4% SBS polymer under the trade name Kraton 1101 CM. The hydrated lime was dosed into the stone mastic asphalt mixture to replace 30% of the filler mass. Pavement surface condition after 12 years of service life was very good. In 2011, bitumen samples were extracted from stone mastic asphalt and tested. The tests were performed on the samples that contained fatty amine and hydrated lime as adhesive agents, obtained from stone mastic asphalt wearing course layer in the rut paths and from between the area limited by rut paths. The hydrated lime additive was found to have a positive effect on rheological properties of the recovered bitumen providing resistance to the water and frost

Modelling the critical concentration of mixed filler in mastic with synthetic wax

This article presents the results of tests of mastic containing mixed filler (limestone dust/hydrated lime) and Fisher-Tropsch synthetic wax. Synthetic wax content was controlled up to 3% (w/w). The ratio of filler in the bitumen was from 0.5 to 3 (w/w), with hydrated lime content of up to 30% w/w. The rheological properties of different mastic compositions were determined with a rheometer equipped with two parallel plates at 60°C using oscillating load. The primary purpose of the article was to determine the nature of mastic stiffness changes in the context of using hydrated lime and synthetic wax as the filler. Consequently, the article proposes a method for evaluation of the critical value of the filler phase in the phase of bitumen modified with synthetic wax. The proposed model of the mathematical function was used to determine the nature of mastic structuring throughout the range of the experiment. The model was also used to determine the critical concentration of the filler in the bitumen phase. It was demonstrated that below the critical filler concentration the mastic behaved in a significantly different manner from the behaviour observed above this critical concentration. When the critical concentration of the filler was exceeded, it resulted in an excessive increase of mastic stiffness, which was considered in the model