Laboratory and Field Evaluation of RAP for Cement Concrete Pavements
01 Jun 2020-Vol. 146, Iss: 2, pp 04020011
TL;DR: In this article, the feasibility of coarse reclaimed asphalt pavement (RAP) for dry lean concrete (DLC) and pavement quality concrete (PQC) mixes is assessed through laboratory and field experiments.
Abstract: In the present study, the feasibility of coarse reclaimed asphalt pavement (RAP) for dry lean concrete (DLC) and pavement quality concrete (PQC) mixes is assessed through laboratory and fie...
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TL;DR: In this paper, the flexural strength of pavement concrete is estimated using logarithmic and power equations that allow the estimation of the flexure strength of a concrete mix that incorporates Reclaimed Asphalt Pavement (RAP) as a function of its compressive strength.
Abstract: The flexural strength of pavement concrete is generally deduced by testing beams or by applying empirical equations. In this investigation, concrete mixtures were manufactured, incorporating 0, 20, 50 and 100% Reclaimed Asphalt Pavement (RAP), by weight, as a replacement for natural aggregates. The compressive strength was measured using cubic specimens and the flexural strength was measured for three types of specimens; beam, semicircular (SCB) and modified beam. This study proposes logarithmic and power equations that allow the estimation of the flexural strength of a concrete mix that incorporates RAP as a function of its compressive strength. Linear or power models are proposed to predict beam flexural strength from SCB specimens and a logarithmic model for modified beam specimens. Statistical analyses show that the proposed prediction models can be considered sufficiently accurate and their use is justified.
3 citations
31 Jan 2017
2 citations
11 Nov 2022
TL;DR: In this paper , Zirconia silica fume (ZSF) is used as an admixture that partially replaced the ordinary Portland cement (OPC) in the concrete mix.
Abstract: AbstractIn the recent period, major importance has been given for the development of concrete pavements rather than flexible pavements. These flexible pavements consist of more than 30–40% high quality aggregates which may be reused in the construction of new roads. Furthermore, due to the paucity of natural aggregates (NA) and environmentally friendly materials, reclaimed asphalt pavement (RAP) is frequently used as a substitute material for the construction of road. In this context, the aim of this study is also to define the optimum range of these RAPs as an alternative of the natural aggregate (NA) for sustainable pavement structures. In the present research, the different proportions of RAP content (coarse and fine) are about 25–50%of the natural aggregate that has been used in the concrete mix. Also, zirconia silica fume (ZSF) is used as an admixture that partially replaced the ordinary Portland cement (OPC) in the concrete mix. In this study, various proportions of ZSF (10, 20, 30 and 40%) were added for the improvement of the mechanical properties of rigid pavement. . This experimental study investigated the performance of high RAP content and ZSF on compressive strength (CS), tensile strength (TS), flexural strength (FS), and water permeability of rigid pavement (RP). The experimental results indicate that the presence of ZSF improves the workability of the wet concrete mixes. However, excessive (more than 40% of the natural aggregate) use of RAP reduces the CS and TS of concrete. The overall result indicates that the performance of 30% fine RAP with admixtures (ZSF) is better as compared to the virgin aggregate in the concrete mixes. The final results were statistically evaluated by two-way factor variance analysis (ANOVA).KeywordsRAPRigid pavementSustainable pavementStrength of concreteZSFANOVA
2 citations
TL;DR: In this paper , the authors explored recycling RHA and RAP in cement stabilised macadam (CSM) to produce a pavement base material and found that the compressive strength, resilient modulus and tensile strength of CSM increased with curing time while the increasing rate and strength after curing decreased with the addition of RHA.
Abstract: High silicon dioxide content enables as a cement substitute. This study explored recycling RHA and RAP in cement stabilised macadam (CSM) to produce a pavement base material. Laboratory experiments covering strength, flexibility, shrinkage, and resistance to temperature variation were conducted on CSM with RAP (40% by weight of natural aggregates) and RHA at 0%, 20%, 40%, 60%, and 80% weight of cement. The results indicated that the compressive strength, resilient modulus, and tensile strength of CSM increased with curing time while the increasing rate and strength after curing decreased with the addition of RHA. The resistance to thermal changes, moisture loss, and the freeze-thaw cycle could be maintained by replacing 20 wt.% (or lower content) cement with RHA. These findings suggest that replacing 20 wt.% of cement with RHA and 40 wt.% of natural aggregates with RAP can generate qualified and environmental pavement base material.
2 citations
TL;DR: In this article , the feasibility of using reclaimed asphalt pavement (RAP) aggregates as a replacement for natural aggregates will improve the porosity and permeability of PC pavement mixtures.
Abstract: Pervious concrete (PC) is emerging as a novel pavement material for its unique characteristics of reducing storm-water runoff and mitigating urban heat islands. This makes it well suited for low-volume pavement applications. It is also expected that reclaimed asphalt pavement (RAP) aggregates as a replacement for natural aggregates will improve the porosity and permeability of PC pavement mixtures. As a result, this study checks the feasibility of using RAP-based PC mixes in a parking space. The construction process will offer a guide to the field engineer on how to push this technology further when recycled materials are used. The PC parking space, with a capacity of 5 tonnes laden weight, was developed by replacing natural aggregate with 25% RAP aggregate (30% of 10 mm and 70% of 4.75 mm). Field mixtures were found to have higher porosity and lower density when compared with laboratory-prepared mixes. The field infiltration capacity was observed to be in the range of 0.50–1.75 cm/s while maintaining a flexural capacity of 2.36 MPa to 3.17 MPa (342.28 pounds per square inch (psi) to 460 psi). This suggests that using binary-graded RAP aggregates helps create an interconnected pore network, enhancing PC mixtures’ transport capabilities. The present study illustrates the step-by-step construction process of PC pavements for field applications. Based on the findings, it is recommended that 50% could be the maximum feasible limit for the usage of RAP aggregates in PC field mixes.
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TL;DR: In this paper, a one-dimensional mathematical model was developed, based on the fundamental energy balance, to calculate the pavement near-surface temperatures using hourly measured solar radiation, air temperature, dew point temperature, and wind velocity data.
Abstract: A one-dimensional mathematical model was developed, based on the fundamental energy balance, to calculate the pavement near-surface temperatures using hourly measured solar radiation, air temperature, dew-point temperature, and wind velocity data. An analysis was conducted to predict the diurnal temperature effects of pavement thermophysical properties with the aim of seeking an optimum composition of paving materials for future infrastructure projects. Appropriate paving materials not only ensure stability and safety for road users, but also the ability to mitigate heat absorption and high surface temperatures contributing to the Urban Heat Island Effect and human comfort. This paper evaluated the effects and sensitivities of the thermophysical properties on the pavement surface temperatures. The results indicated that both albedo and emissivity have the highest positive effects on pavement maximum and minimum temperatures, respectively, while increasing the thermal conductivity, diffusivity, and volumetric heat capacity help in mitigating the maximum but not the minimum pavement near-surface temperature.
238 citations
TL;DR: In this article, the authors investigated the mechanical properties of RAP-incorporated Portland cement concrete and found that the energy absorbing toughness for the RAP incorporated concrete has been significantly improved.
221 citations
TL;DR: In this paper, the authors evaluated the effectiveness of rejuvenator agents in improving the aged binders' properties and the recycled mixture performance and concluded that totally recycled asphalt pavement can be a good alternative for road paving, especially if rejuvenators are used to reduce their production temperature and improve their performance.
Abstract: The recycling of reclaimed asphalt pavement (RAP) helps road authorities to achieve their goal of a sustainable road transport system by reducing waste production and resources consumption. The environmental and economic benefits of using RAP in hot mix asphalt (HMA) applications could be pushed up to the limit, by producing totally recycled HMAs (100% RAP), but the performance of this alternative must be satisfactory. In fact, these mixtures could possibly present problems of workability and durability, higher binder aging and low fatigue cracking resistance. Thus, the objective of this study is to determine if totally recycled HMA mixtures could be a good solution for road paving, by evaluating the merit of some rejuvenator agents (commercial product; used engine oil) in improving the aged binders’ properties and the recycled mixture performance. Several binder samples were prepared with the mentioned rejuvenators and characterized (Pen, R&B and dynamic viscosity), in order to select the best rejuvenator contents. The production temperatures of the corresponding recycled mixtures were evaluated based on their workability. Totally recycled HMAs were produced with the best previously observed combinations, and their performance (water sensitivity, rutting resistance, stiffness, fatigue resistance, binder aging) was assessed. The main conclusion of this study is that totally recycled HMAs can be a good alternative for road paving, especially if rejuvenator agents are used to reduce their production temperature and to improve their performance.
186 citations
TL;DR: Recycled asphalt pavement (RAP) is the removed and/or reprocessed pavement material containing asphalt and aggregate as mentioned in this paper, which has become common practice in the constructi...
Abstract: Recycled asphalt pavement (RAP) is the removed and/or reprocessed pavement material containing asphalt and aggregate. The use of RAP in asphalt pavement has become common practice in the constructi...
140 citations
TL;DR: In this article, the effects of rice husk ash (RHA) on the mechanical properties of roller compacted concrete (RCC) designed with original and reclaimed asphalt pavement (RAP) materials were considered.
133 citations