•A new sustainable half warm emulsified bituminous mixture has been developed.•The moisture sensitivity improved by incorporating waste glass.•Rutting resistance for the half warm mixtures was lower ...than for the cold mixture.•Post treatment using microwave energy was an effective technique to produce half warm emulsified bituminous mixture.
Sustainability and materials recycling have increasingly acquired importance in various aspects of life. It has well known that95% of roads are paved with hot mix asphalt (HMA),theirrawmaterials require a lot of energy to prepare and lead to the releaseof a considerableamount of CO2 into the environment. As a result, developing new technologies to prepare a new sustainable asphaltic mixture that consumes less energyand is eco-friendly becomes a necessity. This research aims to develop a sustainable half-warm asphalt mix by exposing the cold bituminous emulsion mixture (CBEM) to a post treatment using microwave energy technique, as well as utilising crushed glass waste as fine aggregate. The newly developed mix (half warm bituminous emulsion mixture, or HWBEM) is evaluated in terms of two main failure distress (cracking and rutting) using wheel track (WTT) and indirect tensile tolerance index, or cracking tolerance index (CT-index), in addition to the volumetric and durability evaluation in term of air voids content (AV) and retained Marshall stability test (RMS). Tests results regarding mechanical, volumetric, and durability properties indicated that the developed mixture was relatively comparable in some of the properties with referenced CBEM and superior in one aspect. Moreover, the sustainability aspect was achieved successfully by replacing a significant amount of virgin fine aggregate with the crushed waste glass. Based on the results of the test program, it can be said that the newly developed HWBEM incorporated waste glass can work as a structural surface layer.
Sustainability has recently gained a high profile in many fields. Construction, due to its huge demand to materials, is one of the important targets. More than 95% of roads are paved with hot mix ...asphalt (HMA). Production of HMA using virgin materials consumes a lot of energy and contributes to the emission of a considerably large volume of CO
2
. Therefore, the replacement of virgin materials with waste and extending material life is of considerable value. Half-warm bituminous emulsion mixture (HWBEM) is a cold bituminous emulsion mixture subjected to a moderate heating energy before the compaction process. This study aims to evaluate the extent of enhancement in HWBEM crack resistance using a low energy heating technique (i.e., microwave) where virgin fine aggregates within the mixture were replaced with waste crushed glass. In addition to the measurement of volumetric properties and mixture sensitivity to moisture damage, crack related tests of indirect tensile strength test (ITS), cracks resistance test (Ideal-CT test), fracture energy (
G
f
), cracking resistance index (CRI) and toughness index (TI) were conducted to evaluate mixtures tensile strength. Test results showed that the procedure followed to prepare HWBEM containing waste crushed glass worked out and prevented cracking failure. It was concluded that adopting ITS is not sufficient to reflect all mixture behavior phases when resistance to the tensile cracking is the concern, as it depends on the peak load only. Other indices, such as CT-index, depend on more than one parameter and reflect a reasonably more realistic evaluation.
Evapotranspiration represents one of the main parameters in the hydrological cycle. It is usually expressed by the term Reference evapotranspiration (ETo), that is affected by some meteorological ...parameters. This study aims to find the difference amount in reference evapotranspiration (ETo) between urban and suburban quarters in Karbala city. Study methodology includes selecting once urban area and four suburban quarters. Two methods of determining the reference evapotranspiration were applied. First, a direct method which measured reference evapotranspiration (ETo) at selected fields by using a hand-held device. Second, an indirect method was used Penman-Montieth equation. The findings showed that magnitudes of reference evapotranspiration (ETo) by Penman-Montieth equation are higher than the values measured by the direct method for urban and suburban quarters. Also, it was found that the absolute percentage of difference in the average amount of reference evapotranspiration (ETo) between urban and suburban quarters is 13% by using the direct method and 61% by using Penman-Montieth equation. Study conclusions are suburban area has higher magnitude of reference evapotranspiration (ETo) than urban quarter by using any of direct method and indirect method (Penman-Montieth equation).
Scientists have effectively demonstrated that the introduction of a waste product comprising cementitious chemical compositions can enhance the mechanical properties and durability of cold bitumen ...emulsion mixes (CBEMs). On the other hand, the high air void content of the CBEM mix remains a challenge that is considered unsatisfactory by paving engineers. As a result, this investigation highlights two major changes that were made. The first is the use of waste paper sludge ash (PSA) as a filler in CBEM instead of the conventional mineral filler (CMF). The second change was made to further improve the mixture by reducing the amount of CBEM air voids using microwave (MW) heating energy as a post-treatment method. When compared to typical hot mix asphalt (HMA), the new CBEMs showed great mechanical properties and durability. Moreover, the proposed method, using CBEMs, has lower environmental risks, is safer, and is more cost-effective than existing paving mix technologies. This study presents a method for controlling air voids within pavement specifications without affecting mechanical behaviour or generating additional environmental or economic considerations. When compared to typical mixtures, laboratory test results showed that MW-heating can enhance both the stiffness modulus and the air void content. Furthermore, these results revealed a minor reduction in creep stiffness and water sensitivity. Nevertheless, in terms of mechanical, volumetric, and economic properties, the suggested post-mix treatment was comparable to HMA. The findings point to the need to adopt CBEM post-heating approaches, particularly the MW treatment procedure.
Certain disadvantages could have appeared while using hot mix asphalt (HMA), such as the release of unhealthy gases into the environment (environmental issues), difficulty in sustaining the ...temperature over long distances (logistical issues), and consuming a sufficient amount of energy while preparing and laying down (practical and economic issues). To overcome the aforementioned issues, this study aimed to develop rapid-curing emulsified asphalt cold mixes (EACM) comprising a cementitious filler made from industrial by-product materials. Paper sludge ash (PSA) is used as an active filler for application in the EACM rather than conventional mineral filler. Additionally, to maximize the effect of PSA’s hydraulic activity, incinerated sewage ash (ISA) is utilized as an activator at a concentration of 0%–4% by mass of the aggregates. The results demonstrate that the use of waste PSA significantly improves the indirect tensile stiffness modulus (ITSM) by around 10 times more after 2 days than the traditional emulsified asphalt cold mixes. In addition, the improvement in ITSM was around 30% and 65% for 6%PSA+1%ISA and 6%PSA+4%ISA mixes, respectively. Furthermore, the rutting for the 6%PSA+1%ISA and 6%PSA+4%ISA mixes decreased to around 19% and 11% in comparison to the traditional 131-pen HMA. The formation of hydration products and rapid demulsification of asphalt emulsion, which results in binding within the mixtures, are responsible for the increased ITSM and rutting resistance. As a result, environmental issues are minimized, and energy preservation may be maintained.
The aim of this research was to develop a sustainable and ecologically sound, non-traditional cold mix asphalt (CMA) that can be used in the construction industry. This new type of CMA incorporates ...wastewater sludge fly ash (UFA) and bottom ash (UBA) as a replacement filler for ordinary Portland cement and limestone. Silica fume (SF) was also used as an additional filler. The mechanical and durability characteristics of the new CMAs were examined in terms of indirect tensile stiffness modulus (ITSM), and rutting, fatigue, water and fuel resistance. The results showed that CMA with 2.1% OPC +3.9% UFA at 3 days of age, had ITSM values 11 times that of traditional CMA, while CMA with 2.1% OPC+ 3.3% UFA +0.6% UBA, had ITSM values 5 times that of traditional CMA at 28 days of age. SF activated hydration for both mixes, significantly increasing ITSM. These results indicate that CMA has a comparable mechanical performance to standard Hot Mix Asphalt (HMA) mixtures for use as surface pavement layers. This study offers a novel CMA with improved mechanical performance. It is economically effective and ecologically beneficial, compared to HMA, due to its ability to accommodate wastewater sludge ashes that are often disposed of in landfill sites.
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•Wastewater sludge fly and bottom ash were used in novel CMA mixtures.•A new technology for producing a low carbon CMA, was developed.•High values for indirect tensile stiffness modulus were achieved.•Rutting resistance was investigated using wastewater sludge ash.•There was an improvement in the durability characteristics of CMA containing wastewater sludge ash.
This paper aims to explore the current state of the art and potential of 3D concrete printing and its use in large-scale applications. The study analysed 373 academic research, all of which were ...obtained from the Scopus database. The review conducted on some crucial issues on development of 3D concrete that included materials and their desirable properties, printer nozzle developments, reinforcement in printing, geopolymers as printing materials, and the use of coarse graded aggregates. This study provides researchers and institutions with an in-depth insight into 3D concrete printing and research trends worldwide and assesses the future of 3D concrete printing in large-scale applications. The requirement of more research on the mechanics of 3D printers, standardising a printer nozzle, the automation of reinforcing processes, and use of coarse graded aggregate for large-scale structural application were identified in this review. It also shows how 3D concrete printing has evolved and changed over time and gives an insight into the future of 3D concrete printing—making this scientometric review a framework for future studies.
Abstract
The main concept of using waste and recycled materials as modifiers for construction materials, is to improve their performance, keep the resources, and conserve the environment from ...pollution problems. This investigation is tended to evaluate the effect of using two different types of modifiers on the physical properties of asphalt binder. The modifiers are Recycled-Low-Density-Polyethylene (R-LDPE) polymer and waste-Paper Fiber (w-PF), they were mixed individually and collectively with neat asphalt binder. The first set of modified binders comprised neat binder with 3% R-LDPE alone, the second is comprised 0.3%, 0.5% and 0.7% of w-PF alone, while the third comprised collective modifiers of 3% R-LDPE and 0.3%, 0.5% and 0.7% w-PF. The influence of these modifiers on neat asphalt binder was evaluated in terms of penetration (Pen.), softening point (SP), penetration index (PI), ductility, rotational viscosity (RV), penetration aging index (PAI) and softening point index (SPI). The obtained results indicate that the utilization of modifiers helps in improving the physical properties of asphalt binders by different levels. the modification by collective modifiers leads to an increase SP, RV, PI, PAI, and SPI to 65%, 2 times, 1.044, 0.93, 2.5 respectively compared to neat bitumen. As well, leads to a decrease in both Pen. and ductility to the levels 45% and 79% respectively. This indicates that the use of waste and recycled modifiers especially in the combined form encourage the production of comparative modified asphalt binder.
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