Aggregate Base Layer Research Articles

Comparison of Lab vs. Backcalculated Moduli of Virgin Aggregate and Recycled Aggregate Base Layers

The resilient modulus (MR) and the backcalculated modulus from the FWD testing (EFWD) of the unbound layers are critical inputs in the analysis/design of pavements. Several studies have tried to develop a conversion factor between these two parameters, while the nonlinear stress dependency of unbound materials and the pavement strain response are mostly missing from the literature. This study aims to compare the laboratory-measured MR of recycled aggregate base (RAB) materials and a virgin aggregate base using field-based EFWD and tries to establish pavement’s responses to loading using vertical strains from both the MR and EFWD values of the respective materials as comparability parameters between the two. For this purpose, a control virgin aggregate (VA, limestone) and three types of RAB materials were selected to construct four test sections. The test sections were modeled in layered elastic- and finite-element-based pavement response models to calculate the vertical strains at the mid-depth of the base and top of the subgrade layers. A comparison of the lab-calculated vertical strains using MR with actual vertical strains in the field from EFWD showed that there was no relationship between the two stiffness parameters in all tested RABs. The vertical strains, based on the lab MR, undermined the stiffness of the recycled aggregates in the field. In contrast, the values of EFWD based on the vertical strains remained close to the MR strains of limestone (VA) throughout the testing period, establishing an EFWD vs. MR relationship (MR = 0.87 EFWD). The results also show that fine RCA was a better-performing material over three years. This research not only explores how the hydration process in RABs limits the development of MR-EFWD correlations but also underscores the need to consider real-world conditions when assessing their performance.

Macroscopic and Microscopic Investigation of Gypsum Slag Cement-Stabilized Recycled Aggregate Base Layers.

The purpose of this study is to investigate the macro and micro properties of stabilized recycled aggregate base layers using gypsum slag cement (GSC) and compare them with ordinary Portland cement (OPC). To achieve this, four levels of recycled aggregate content (0%, 50%, 60%, 70%) and three levels of binder materials (3.5%, 4.5%, 5.5%) were designed, where the binding materials included OPC and GSC. When GSC is used as the binding material with 0% recycled content, two scenarios for the ratio of slag to activator are considered: 4:1 and 4:2. For recycled content of 50%, 60%, and 70%, only the 4:1 ratio is considered. The macro-mechanical properties of the composite material were studied through compaction tests, unconfined compressive strength tests, and indirect tensile strength tests. Microscopic properties were investigated through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Macroscopic test results indicate that, at an equal binder content, GSC exhibits a higher moisture content and maximum dry density compared to OPC. Moreover, the unconfined compressive strength and indirect tensile strength of GSC are higher than those of OPC. Microscopic test results reveal that the hydration products of both binding materials are essentially similar; however, under identical curing conditions, the hydration products of GSC are more abundant than those of OPC.

Thermal contraction coordination behavior between unbound aggregate layer and asphalt mixture overlay based on the finite difference and discrete element coupling method

AbstractThe constraint action of the unbound aggregate layer underneath plays an important role in affecting the temperature strains in the top asphalt layer. The focus of the present paper is to investigate the interactive thermal contraction mechanisms between the asphalt mixture and granular base layers to offer a new perspective in promoting the understanding of the thermal cracking disease. In this paper, both experiments and simulations were conducted for the thermal contraction tests. A novel numerical modeling of virtual composite structures was proposed using wall‐zone coupling operation based on the finite difference and discrete element coupling method. The experimental composite structures containing three types of asphalt mixture overlays and five types of unbound aggregate base layers were developed for verification. The thermal contraction and restraint mechanism were revealed from both macro and microscopic scales. The proposed numerical modeling shows a 94% high accuracy. The particle displacement vector and contact force chain could explain the thermal contraction behavior of composite structures. Smaller particle motion displacement or stronger contact force chain result in a higher restraint strain of the asphalt overlay. The thermal contraction behavior can be coordinated through the compaction and loosening of unbound aggregates. The material parameters and cooling temperature differences in the asphalt overlay have slight effects on the constraint action of a base layer, while the gradation and mechanical parameters of the unbound aggregate layer show significant impaction. The parameters, cohesion C and friction angle φ, show a quadratic function with the restraint coefficient. This work has significant guidance on the selection of pavement structure and materials to improve the thermal cracking problem and lay the basis for the mechanical theoretical calculation to predict thermal cracking.

COST AND TIME ANALYSIS USING THE CRASHING METHOD ON THE PROBOLINGGO – BANYUWANGI TOLL ROAD PROJECT PEKET 2: STA 9+000 – 20+200

The government is building toll roads in various regions in Indonesia to realize economic acceleration and minimize economic inequality in society. However, based on facts on the ground, there are still many delays in toll road construction projects which are detrimental so it is necessary to take steps to accelerate the work. The aim of this research is to analyze the time and costs of accelerating the Probolinggo – Banyuwangi Toll Road construction project STA 9+000 – 20+200 using the Crashing Method. This type of research is quantitative research with the research subject being PT. Hutama Karya Indonesia (HKI) as the project implementing contractor. The research uses secondary data, namely the Draft Expenditure Budget (RAB), Schedule, weekly reports, and project costs for the completion of Toll Road construction work. The data collection method was carried out using observation and documentation methods. The research data analysis technique uses the Crashing. The results of research state: 1) On work on the Probolinggo – Banyuwangi Toll Road project Job STA 9+000 – 20 +200 job time can be accelerated to 311 days, which originally lasted 394 days. 2) Application of the Crashing Method to the Probolinggo Toll Road project– Banyuwangi STA Jobs 9+000 – 20+200 with critical path on public works, workplace cleaning, earthworks, drainage, sub grade, aggregate base layer, pavement, work others, traffic light lighting and electrical works, plazas Tolls, and work on toll facilities and toll gate offices can saving 115 days of work time with additions cost Rp. 72,941,450,191.64.

Local Stiffness Assessment of Geogrid-Stabilized Unbound Aggregates in a Large-Scale Testbed

This paper integrates and extends an earlier article presented at the 20th International Conference on Soil Mechanics and Geotechnical Engineering. The generation of a stiffened zone in the proximity of a geogrid is one of the primary mechanisms of mechanical stabilization of pavement unbound aggregate layers using geogrids. This paper focuses on the quantification of the stiffened zone through a local stiffness assessment using bender element (BE) sensors. Unbound aggregate base layers were constructed in a large-scale laboratory testbed. Geogrid-stabilized layers had geogrids with different-sized triangular apertures contributing to the geogrid-stiffened zone. Shear wave velocities were measured at three different heights using BE sensors, and the vertical stiffness profiles of the mechanically stabilized aggregate layers were evaluated. In addition, the conversion method between small-strain stiffness and large-strain stiffness was established from the repeated load triaxial tests with BE pairs to transform the vertical stiffness profile into that of the resilient modulus. Furthermore, dynamic cone penetration (DCP) and light-weight deflectometer (LWD) tests were performed at multiple locations into the stabilized and unstabilized unbound aggregates. From the large-scale experimental study, the local stiffness improvement owing to the geogrid enhancement was up to 16.2% in the vicinity of the geogrid location, and the extent of the local stiffened zone evaluated through various test methods was between 15.2 cm (6 in.) and 25.4 cm (10 in.) above the geogrid.

Analisis Karakteristik Material Lokal Kinang Jingkion dari Quarry Apalapsili, Habie Dan Hulikma, Serta Komposisi Campuran Terbaik Untuk Digunakan sebagai Bahan Lapis Pondasi Agregat Kelas A

The main road pavement works carried out in Yalimo Regency are flexible pavements using asphalt as the main adhesive. Asphalt produced outside Papua Island is transported to Jayapura using sea transportation, then transported to Wamena using air transportation, then transported to Yalimo Regency using land transportation, of course the price is not cheap when it arrives in Yalimo Regency. In addition to the price factor of asphalt material due to the relatively high transportation services, another thing that becomes a consideration for the need to use Kinang Jingkion material is the ease factor in working on roads using Kinang Jingkion which allows the local community to work on it using standard equipment that does not really require treatment or specific technology. According to these problems, further research on Kinang Jingkion material is urgently needed. Analysis of the Characteristics of the Local Material of Kinang Jingkion from the Apalapsili, Habie and Hulikma Quarry, and the Best Mix Composition to be Used as a Class A Aggregate Base Layer presents the results of the analysis related to the characteristics of the local Kinang Jingkion material taken from 3 different quarries namely Apalapsili, Habie and Hulikma, as well as results of testing the composition of the mixture to be used as a Class A Aggregate Base Layer.

Evaluation of Airport Pavement Base Layer Stiffness Characteristics via Embedded Field Sensors

Real-time stiffness monitoring of unbound aggregate layers using embedded field sensors is crucial for advanced airport pavement design and management. This paper describes research findings on monitoring base layer stiffness characteristics for airport pavements using an embedded bender element (BE) field sensor, inductive coil sensors, and pressure cells. A full-scale pavement test section was constructed at the Federal Aviation Administration (FAA)’s National Airport Pavement Test Facility (NAPTF). A BE field sensor, inductive coil sensor pairs, and pressure cells were installed in the unbound aggregate base to evaluate the layer stiffness, applied load stress, and deformation characteristics. A triple dual tandem gear loading module applied 58,000 lb per wheel to the tested section with a wander pattern consisting of 66 passes arranged in nine lateral wander positions. Dynamic responses of coil sensors and pressure cells were collected during the traffic test, whereas BE signals were collected after completing each wander pattern. Laboratory repeated load triaxial tests with BE instrumentation were also conducted to establish a correlation for converting BE field sensor readings to layer modulus properties. The in situ modulus characteristics of the aggregate base layer were evaluated during full-scale testing using two methods: shear wave velocities from a BE field sensor, and strain and stress measurements from coil sensors and pressure cells. The moduli estimated using both approaches fell into typical ranges of crushed aggregate bases and were highly comparable. The moduli from the dynamic sensor measurements clearly showed the effect of vehicle wander on aggregate base layer measured responses.

Calculation of Cost Budget Plan and Development of Implementation Method on Preservation of Aceh Selatan/Subulussalam Boundary Road - Sumut Province Boundaries

Cost Budget Plan is a calculation of the amount of money needed for materials, tools and wages, as well as other costs related to project implementation. Goals to be achieved to recalculate the budget Road Reconstruction Workand the method of implementation in which there are work methods for tools, K3, quality control, and the S curve regarding cost, quality and the right time. The results obtained from the calculation, Preservation Reconstruction of the South Aceh Boundary Road / Subulussalam -Boundaries of North Sumatra Province The total budget cost is Rp. 3.412.934.913.00 As well as scheduling the implementation time using the S curve. The preparation of the Implementation method applied to the Project includes Ordinary Excavation, Asphalt Pavement Excavation without Cold Milling Machine, Grain Pavement Excavation, Selected Piles from excavation sources, Road Body Preparation, Grade Aggregate Foundation Layer A, Class B Aggregate Base Layer, Binder Impregnating Layer - Liquid/Emulsion Asphalt, Binder Impregnating Layer - Liquid/Emulsion Asphalt, Laston Wear Layer (AC-WC), Laston Intermediate Layer (AC-BC), Laston Foundation Layer (AC- base), Anti-flaking agent, Thermoplastic Road Marking, Hot Mix Asphalt Improvement, and Plant Control. in an effective way based on the plans.

Investigation of Shear Strength of Subbase-Subgrade Interface with Geosynthetics Reinforcement Utilizing A Large-Scale Direct Shear Test

Geosynthetics are being used to strengthen road pavement. Geosynthetic inclusions improve pavement carrying capacity, maintenance costs, highway service life, reflective cracks, and undesirable large lateral and vertical deformations. The primary purpose of this research is to determine the effectiveness of geosynthetics (geogrids and geotextiles) in stabilizing the subgrade and reinforcing the base course layers in unpaved test sections. Determine the mechanical interaction of subgrade soils (clay and sand) and aggregate road base layers (subbase) with and without reinforcement. Compute the shear strength parameters (cohesion, friction angle, and interface coefficient factor). Therefore, Large-scale direct shear experiments in the laboratory were performed on subbase-subgrade materials with and without geosynthetics, under the applying normal of stresses (25, 50, 75, and 100) kPa, indicating the quantity overburden the pressure in paving. The present research uses a large-scale direct shear apparatus with an up square box (200 mm×200 mm×100 mm) and a bottom rectangular box (200 mm×250 mm×100 mm). A direct shear test was implemented by manufacturing this equipment. The results obtained from experiments showed that biaxial geogrid G1 has the best behavior for both (subbase-clay) and (subbase-sand) and has an interface shear coefficient factor more significant than unity and equal to 1.05 and 1.02, respectively.

Effect of various interface bonding conditions on critical response characteristics for cracking potential of asphalt pavements

Interface bonding conditions are important to ensure the desired performance of multi-layered asphalt pavements. Most previous studies only investigated the sole effect of the interface at a specific location, although the most extreme case is when poor bonding occurred at multiple locations simultaneously. Also, the sensitivity of bonding effects to structural parameters is unclear. Therefore, this study investigated the effects of multiple bonding scenarios and structural parameters on critical responses, the 3-D viscoelastic finite element model. The results indicated that critical locations for cracking potential depend on bonding scenarios. Interface bonding between asphalt and aggregate base layers mainly contributed to bottom-up cracking, while the interface between asphalt layers was more associated with top-down and near-surface cracking. In addition, the use of a thicker asphalt layer was more effective than the use of a strong base layer to mitigate the negative effects of poor bonding conditions.

Evaluation of long-term performance of recycled aggregate base (RAB) layers and optimization of their design thicknesses

To reduce the use of natural aggregates commonly used in base layers, constructing recycled aggregate base (RAB) layers has gained popularity. However, in the literature, there is limited information about the engineering properties of recycled concrete aggregate (RCA) materials with different gradations and the blends of RCA and recycled asphalt pavement (RAP) materials. There is also a lack of practice in using a mechanistic-empirical (ME) design method to optimize RAB layer thicknesses. In this study, several full-scale test cells were built with RAB and natural aggregate base layers, and the physical and engineering properties of the base layer aggregates were determined in the laboratory. For long-term performance evaluation of the cells built in the field, falling weight deflectometer (FWD) tests were performed, rutting measurements were taken, and soil temperature was monitored over a period of two years. An ME design procedure was used to optimize RAB layer thicknesses.

Evaluation of Engineering Properties of Recycled Aggregates and Preliminary Performance of Recycled Aggregate Base Layers

Although there have been several studies about using recycled aggregates to construct recycled aggregate base (RAB) layers, there is a lack of information about the effects of gradation of recycled concrete aggregate (RCA) materials on the performance of such layers. There is also limited information available regarding the use of RCA and recycled asphalt pavement (RAP) materials together in RAB layers. In this study, three test cells were constructed with RAB layers using two different RCA materials with different gradations and a blend of RCA and RAP materials, and another cell was constructed with a natural aggregate base layer. Physical characteristics of the base layer aggregates were determined, and resilient modulus (MR) tests were performed. A series of falling weight deflectometer (FWD) tests were performed in the field, and changes in air and soil temperatures over time were monitored. This paper contains detailed information about the evaluation of the engineering properties of recycled aggregates and the preliminary performance of the constructed RAB layers.

Monitoring Particle Movement under Compaction using SmartRock Sensor: A Case Study of Granular Base Layer Compaction

The quality of base course compaction significantly influences pavement’s overall performance. Compared with conventional compaction methods, the intelligent compaction (IC) uses external accelerometers to track pavement responses during compaction and correlates them with pavement layer characteristics to improve the compaction quality. Very few studies have attempted to present interactions of granular materials from the particle level, i.e., how individual particles are responding under the compactive effort. The recent development of a prototype wireless sensor, SmartRock, made tracking the particle movement at meso-scale possible. Accordingly, this paper has the objective of applying the SmartRock sensors to monitor the motion characteristics (i.e., translation and rotation) of granular particles during the compaction process and evaluate the particle response patterns as insights into understanding the compaction mechanism of the unbound aggregate base layer. The experimental site selected was an airport runway test section, designated as the Smart Runway project located in Hill Air Force Base (AFB) in Layton, Utah, United States. SmartRocks were embedded at the bottom of the granular base layer to collect particle motion data during compaction. Analysis results indicated that particle’s motion behavior was closely related to the compactive effort and material properties. Compaction is a process of gaining interlocking among particles and elasticity in materials, and is achieved through the particle’s three-axial angular position arrangement and vertical translation. The particle movement characteristics observed in the granular base were compared to those in asphalt mixtures, which confirmed the unique responses of bound and unbound pavement layer materials. It is suggested that the characteristics of particle rotation behavior during compaction can potentially be used as a control parameter to monitor compaction conditions.

Airport Pavement Stiffness Monitoring and Assessment of Mechanical Stabilization using Bender Element Field Sensor

The bender element (BE) field sensor is a newly developed embedded pavement instrumentation that measures shear wave velocity to estimate constructed layer moduli of unbound aggregate bases and subbases. This paper presents findings related to monitoring stiffness characteristics of airport pavement base courses instrumented with BE field sensors and tested under full-scale accelerated pavement testing during Construction Cycle 9 (CC9) of the National Airport Pavement Test Facility (NAPTF) by the U.S. Federal Aviation Administration (FAA). The CC9 aggregate base courses were constructed following FAA’s P-209 specification for a geosynthetic experiment using a biaxial geogrid installed at the bottom of the 8-in. (203-mm) thick base in the north test section, while the control pavement in the south test section was built without a geogrid. Two BE field sensors were installed in the north and south test sections approximately 1 in. (25 mm) above the base–subbase interface. Multiple stages of aircraft gear loads, including static dual-gear, dynamic slow-roll (moving wheel), and dynamic proof-roll, were applied to the test sections. BE field sensor data collected throughout multiple loading stages were used to investigate the stiffness characteristics of the pavement base. These preliminary tests conducted at the NAPTF CC9 experiment revealed the effects of static and dynamic aircraft gear loads on the stiffness of the aggregate base layer and how confinement influenced the moduli of the geogrid-stabilized base. Further, previously observed anti-shakedown effects caused by vehicle load wander could be quantified through changing base course modulus and deformation behavior from the BE field sensor data analysis.

Construction and performance evaluation of large stone subbase (LSSB) layers

The most appropriate way to evaluate the engineering properties of large stones is to perform field testing on full-scale pavement systems built with large stone subbase (LSSB) layers because such properties of large stones cannot easily be measured in the laboratory. Although there have been several studies discussing the use of large stones in pavement systems, there is still limited knowledge about appropriate thicknesses, use with geosynthetics and/or with recycled aggregates, and long-term performance of LSSB layers. In this study, several test cells were constructed with LSSB layers with different thicknesses. The cells contained different recycled aggregate base (RAB) layers, and some of the cells contained geosynthetics beneath the LSSB layers. Nuclear density tests and intelligent compaction were performed during construction. A series of falling weight deflectometer (FWD) tests were performed during and after construction. One of the cells contained thermocouples embedded at different depths for soil temperature monitoring. This study showed that the use of geosynthetics was essential for constructing LSSB layers that are not thick enough, and staged construction was not convenient for large stones. In addition, the cells constructed using the thicker LSSB layers provided greater performance. In the short term and the long term, the cells containing the thicker LSSB layers yielded around 2.6 and 1.5 times higher modulus values, respectively.

Pavement Optimisation With Aggregate Base Or Asphalt Layers Stabilised With Hexagonal Geogrids

The use of hexagonal geogrids in pavement structures results in the increase of the life of designed structure.This offers the possibility to reduce the thickness of layers without reduction of pavement life, or to increase the traffic capacity of a pavement without the need to increase its thickness. This way of using geogrids in pavements design was introduced to the pavement industry by one producer of hexagonal geogrids as a Pavement Optimisation (PO) concept.It can be transformed into both economic and environmental benefits, and obviously results in savings of natural resources and reduction of carbon footprint of a project. PO with geogrids can be used both in the newly designed pavement structures, and in the asphalt overlays of the existing old pavements. Asphalt overlays enhancement with a geogrid either increases the fatigue life of overlays or allows the reduction of overlays thickness to achieve the same pavement life. In new pavements, stabilisation of aggregate base with geogrids increases the stiffness of aggregate, which increases the performance of a whole pavement. This paper presents several tests results, which confirm beneficial effects of using hexagonal geogrids in asphalt overlays and aggregate base layers, from laboratory to full scale accelerated pavement tests. Also, modifications of Mechanistic-Empirical pavement design method, which allow to implement the geogrid benefits into the design process, are discussed. Finally, case studies of pavements – newly designed and reconstructed – optimised with hexagonal geogrids are presented.

An investigation of structural responses of inverted pavements by numerical approaches considering nonlinear stress-dependent properties of unbound aggregate layer

Inverted pavement has a unique structure that consists of an unbound aggregate base (UAB) layer sandwiched between a thin bituminous surface and a stiff cement-treated base (CTB). The stiffness of the successive pavement layers decreases with the depth, which is different from the conventional flexible pavement. The nonlinear stress-dependent property of the UAB layer plays a critical role in the structural response of the inverted pavement, which contributes to its service performance and durability. This paper presents simulations of 3-D finite element models verified by GTPAVE data to investigate the effect of the UAB layer on the pavement structures. The linear elastic and nonlinear elastic models were applied to both inverted and conventional pavements. The results show that the inverted pavement was more sensitive to the nonlinear stress-dependent property of the UAB layer due to the compaction effect from two stiffer layers of an upper thin AC layer and a lower CTB layer. The stress distribution along the load centerline, deflection along the asphalt concrete (AC) layer, and the stiffness distribution contours within the UAB layer were also investigated to make a comparison of the structural response between the inverted pavements and conventional pavements under the effect of the UAB layer. The comparison study presents that the inverted pavement had better performance and saved more asphalt under the same loading condition: (1) the bottom of the AC layer in the inverted pavement experienced lower tension; (2) the deflection along the AC surface was also much smaller than that of the conventional pavement. In addition, the inverted pavements with different thickness of the UAB layers were compared, which showed that a thicker UAB layer could increase the tensile stress at the bottom of the AC layer but relieve the tension transferred from the bottom of the CTB layer.

Winter Maintenance of Permeable Interlocking Concrete Pavement: Evaluating Opportunities to Reduce Road Salt Pollution and Improve Winter Safety

Permeable interlocking concrete pavement (PICP) is a type of permeable pavement system that uses the joint spaces between pavers to drain water from the surface into an aggregate base and subbase layer below. Because of its ability to rapidly drain surface water, PICP has the potential to reduce the amount of ice formed on the surface during winter conditions compared with traditional impervious pavements. As a result, PICP may reduce the amount of road salt needed for de-icing paved surfaces and may also reduce the risk of pedestrian slipping and vehicle skidding throughout the winter. This study evaluates the performance of an outdoor PICP and asphalt test pad over two winter seasons in Vaughan, Ontario, Canada, by assessing differences in surface conditions, surface friction, and surface temperatures. The results of this study indicate that PICP provides equivalent or higher levels of safety compared with asphalt when treated with de-icing products at medium (0.049 kg/m2) or low (0.024 kg/m2) application rates. Re-freezing of melted snow and ice after sunset was observed on the asphalt surface creating black ice, but not on the PICP cells. Consequently, compared with asphalt pavements, PICP surfaces will require use of less de-icer and will have lower risk of slips and falls for pedestrians, and lower risk of skidding for vehicles throughout the winter.

PRODUKTIVITAS ALAT BERAT DAN BIAYA PELAKSANAAN PEKERJAAN PADA PROYEK PEMELIHARAAN BERKALA RUAS JALAN: SUNGAI LAKUM – PASAR KAMIS (KERTAK HANYAR)

On the project Periodic Maintenance of Road Sungai Lakum Pasar Kamis is a project implemented using heavy equipment. By using heavy equipment, will facilitate and accelerate the course of the project. The tools used must be considered maintenance, because it is very influential on the production tools and costs incurred for the use of the tool. This study aims to analyze the use of heavy equipment in the periodic Maintenance Project of road Sungai Lakum Pasar Kamis by using theoretical analysis based on field data.
 Analyzing the calculation is the productivity and cost of the equipment on the scope of work that is the work of the land, widening work and road shoulder work, grinding pavement work, and asphalt work, using Excel program as a tool in data processing so that the achievement of the use of heavy equipment available in finish the job.
 Based on the calculation obtained the price of theoretical analysis unit based on field data for the work of preferred stockpiles from the source of Rp. 310.994.714,2; Class B aggregate base layer Rp. 76.127.086,04; Aggregate base layer with hill excavation Rp. 59.705.050,39; Class A base aggregate layer Rp. 204.703.029,9; Asphalt lining resap coat liquid Rp. 3.038.436,28; Lataston coating foundation Rp. 306.997.682,6. Where the calculation of unit price based on field data is smaller than the unit price of the bid data.

Quantification of embodied energy and carbon footprint of pervious concrete pavements through a methodical lifecycle assessment framework

This study provided a systematic lifecycle assessment (LCA) methodology that was used to quantify the total embodied energy and greenhouse gas (GHG) emissions involved in construction of a new pavement. Furthermore, a comparative LCA was performed to adjudge the benefits offered by pervious concrete pavement (PCP) over Portland cement concrete pavement (PCCP) for different mixing procedures, and distinct base layers. The system boundaries included the following phases of pavement LCA: raw material production, transportation, and pavement construction. The total embodied energy and GHG emissions were quantified for a functional unit of 1 km single lane road, 3.5 m wide, and 0.35 m thickness. The relative contribution of each component to energy consumption and GHG emissions was estimated and the variability of LCA model parameters was understood using sensitivity analysis. The results dictated that the total embodied energy and GHG emissions in PCP with aggregate base layer were reduced by up to 3% and 2.7%, respectively, compared to that of PCCP with similar configuration. Further, a capital cost analysis was conducted due to non-availability of maintenance and end-of-life data, which indicated that PCP is almost 1.21% costlier than PCCP for RMC mixing, and 4.13% cheaper for in-situ mixing. The conceptual approach developed in this study provided a generalized methodical framework that could be used to assess the environmental credibility of pavement systems for site-specific conditions.