Evaluation of Chemically Stabilized Quarry Byproduct Applications in Base and Subbase Layers through Accelerated Pavement Testing

2019 ◽  
Vol 2673 (3) ◽  
pp. 259-270 ◽  
Author(s):  
Issam I. A. Qamhia ◽  
Erol Tutumluer ◽  
Hasan Ozer ◽  
Heather Shoup ◽  
Sheila Beshears ◽  
...  
Keyword(s):  
Dry Weight ◽  
Flexible Pavement ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Type I ◽  
Soil Pressure ◽  
Wheel Load ◽  
Accelerated Pavement Testing ◽  
Control Section ◽  
Pavement Testing

Research conducted at the Illinois Center for Transportation evaluated sustainable applications of quarry byproducts (QB) or QB blended with coarse recycled aggregates in chemically stabilized base and subbase layers in flexible pavements. In total, eight full-scale test sections, including one conventional flexible pavement with no QB as the control section, were constructed over a subgrade with an engineered strength of 6% California bearing ratio. The test sections were stabilized with either 3% Type I Portland cement or 10% Class C fly ash by dry weight. Fractionated reclaimed asphalt pavements and fractionated recycled concrete aggregates were also used as the recycled coarse aggregates. Based on laboratory tests conducted to determine strength properties of the chemically stabilized samples, QB and recycled aggregates were blended in a ratio of 70% to30% by weight, respectively. A lightweight deflectometer was used to evaluate the quality of the construction and the curing of the test sections. The constructed test sections were then evaluated for performance through accelerated pavement testing (APT) and frequent measurement of surface deformations. The results of APT showed quite a satisfactory rutting performance of all the evaluated QB applications with no observed surface cracking after 135,000 cycles. Four of the test sections were also instrumented with soil pressure cells to measure the wheel load deviator stress on top of the subgrade. The pressure measurements indicated subgrade pressures 3−5 times lower for the stabilized QB sections compared with that of the conventional flexible pavement control section.

Performance of Dowel Bar Retrofitted Concrete Pavement Under Heavy Vehicle Simulator Loading

2003 ◽  
Vol 1823 (1) ◽  
pp. 141-152 ◽  
Author(s):  
John T. Harvey ◽  
Lorina Popescu ◽  
Abdikarim Ali ◽  
David Bush
Keyword(s):  
Load Transfer ◽  
Heavy Vehicle ◽  
California Department ◽  
Accelerated Pavement Testing ◽  
Control Section ◽  
Vehicle Simulator ◽  
Pavement Testing ◽  
Load Transfer Efficiency ◽  
Dowel Bar ◽  
Heavy Vehicle Simulator

The California Department of Transportation uses dowel bar retrofit (DBR) as a rehabilitation strategy for concrete pavements. Two test sections were retrofitted with dowel bars and a third section was designated as a control on US-101 near Ukiah, California. All three sections were subjected to accelerated pavement testing by using the Heavy Vehicle Simulator (HVS). The results obtained with the HVS demonstrated a large improvement in load transfer efficiency (LTE) and decreases in maximum vertical deflections and vertical deflection differences from DBR. LTE was not damaged by trafficking on the sections with DBR and was less sensitive to temperature changes than the control section. Falling weight deflectometer testing showed damage to the interlock at the joint on the control section and no damage on the sections with DBR. Joint and crack deflections and deflection differences increased with trafficking. A total equivalent loading of approximately 11,000,000 equivalent single-axle loads was applied to each of the sections with DBR without failure occurring.

Reinforcement Tensile Behavior under Cyclic Moving Wheel Loads

2013 ◽  
Vol 2363 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Xiaochao Tang ◽  
Angelica M. Palomino ◽  
Shelley M. Stoffels
Keyword(s):  
Permanent Deformation ◽  
Longitudinal Direction ◽  
Flexible Pavement ◽  
Strain Gauges ◽  
Clear Correlation ◽  
Accelerated Pavement Testing ◽  
Traffic Loading ◽  
Individual Strain ◽  
Pavement Testing ◽  
The Individual

Numerous studies have revealed the benefits of using geogrids in a flexible pavement, especially for reducing permanent deformation. One of the questions that remain about the effectiveness of a geogrid in reinforcing of pavement is the extent to which the geogrid is engaged and mobilized throughout its service. This paper presents results of a laboratory study on various geogrid products embedded in flexible-pavement sections. The laboratory-scale pavement sections were subjected to cyclic moving wheel loads by using reduced-scale accelerated pavement testing (APT). During the APT, strains that developed in the geogrids were measured at intervals of loading applications by strain gauges installed in pairs on the upper and lower surfaces of the geogrid ribs. Permanent deformation of the subgrade was also measured at the same intervals of loading applications. The measurements of geogrid strains throughout the construction process indicated that the construction resulted in a considerable prestressing effect on the geogrids. Measurements from the individual strain gauges in pairs showed that the gauges installed on the upper surfaces of the ribs were in compression while those on the lower surfaces were in tension; the situation suggested a significant effect on the flexural deflection of the ribs on the tensile strain measurements from the strain gauges. Furthermore, it was observed that geogrid ribs in the longitudinal direction of traffic loading were not mobilized, while considerable strains were developed in geogrid ribs in the direction transverse to traffic loading. A clear correlation was found between the reinforcing forces developed in the geogrids and the performance of the reinforced subgrade in relation to resisting permanent deformation.

Mechanistic Analyses and Modeling of Pavement Sections Utilizing Sustainable Aggregate Quarry By-Product Applications

2020 ◽  
Vol 2674 (10) ◽  
pp. 614-627
Author(s):  
Issam I. A. Qamhia ◽  
Erol Tutumluer ◽  
Hasan Ozer ◽  
Pranshoo Solanki
Keyword(s):  
Structural Response ◽  
Field Performance ◽  
Fe Analysis ◽  
Falling Weight Deflectometer ◽  
Accelerated Pavement Testing ◽  
Performance Trends ◽  
Control Section ◽  
Pavement Testing ◽  
Falling Weight ◽  
Sensor Errors

This paper presents a modeling study based on finite element (FE) analysis to mechanistically evaluate flexible pavements constructed with quarry by-products (QB). Twelve pavement test sections, a control section, and 11 others incorporating QB as unbound subgrade replacement and chemically stabilized base/subbase applications were evaluated for field performance using accelerated pavement testing (APT). First, falling weight deflectometer (FWD) deflection basin parameters were calculated and compared with critical pavement responses to evaluate the structural adequacies of the QB pavement sections. The moduli of the constructed pavement layers were then backcalculated from the FWD deflections using the GT-PAVE FE analysis program with nonlinear and cross-anisotropic layer characterizations. For stabilized QB applications, the layer properties calculated from this analysis for the base/subbase layers were used to calculate critical pavement responses. The sections were compared using a response benefit parameter, defined as the ratio of maximum resilient surface deflection in a conventional pavement, as the control section, to that obtained for each section having a certain QB application in consideration. According to the results obtained from the APT sections and the mechanistic FE analyses, the measured and calculated FWD deflection basins were successfully matched with individual sensor errors not exceeding 5% for all 12 test sections. The calculated response benefits indicated significant advantages for using cement-stabilized QB applications over fly ash-stabilized QB applications and conventional flexible pavement sections. Considering the pavement structural response benefits and good performance trends observed, major cost benefits can be realized by routine use of these sustainable QB applications.

scholarly journals Strategies for a Circular Economy in the Construction and Demolition Sector: Identifying the Factors Affecting the Recommendation of Recycled Concrete

2021 ◽  
Vol 13 (8) ◽  
pp. 4113
Author(s):  
Valeria Superti ◽  
Cynthia Houmani ◽  
Ralph Hansmann ◽  
Ivo Baur ◽  
Claudia R. Binder
Keyword(s):  
Circular Economy ◽  
A Priori ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Factors Affecting ◽  
Structural Applications ◽  
Adoption Of Innovation ◽  
Decision Making Processes ◽  
Behavioural Factors ◽  
High Level

With increasing urbanisation, new approaches such as the Circular Economy (CE) are needed to reduce resource consumption. In Switzerland, Construction & Demolition (C&D) waste accounts for the largest portion of waste (84%). Beyond limiting the depletion of primary resources, implementing recycling strategies for C&D waste (such as using recycled aggregates to produce recycled concrete (RC)), can also decrease the amount of landfilled C&D waste. The use of RC still faces adoption barriers. In this research, we examined the factors driving the adoption of recycled products for a CE in the C&D sector by focusing on RC for structural applications. We developed a behavioural framework to understand the determinants of architects’ decisions to recommend RC. We collected and analysed survey data from 727 respondents. The analyses focused on architects’ a priori beliefs about RC, behavioural factors affecting their recommendations of RC, and project-specific contextual factors that might play a role in the recommendation of RC. Our results show that the factors that mainly facilitate the recommendation of RC by architects are: a senior position, a high level of RC knowledge and of the Minergie label, beliefs about the reduced environmental impact of RC, as well as favourable prescriptive social norms expressed by clients and other architects. We emphasise the importance of a holistic theoretical framework in approaching decision-making processes related to the adoption of innovation, and the importance of the agency of each involved actor for a transition towards a circular construction sector.

scholarly journals Discrete Element Simulation Analysis of Biaxial Mechanical Properties of Concrete with Large-Size Recycled Aggregate

2021 ◽  
Vol 13 (13) ◽  
pp. 7498
Author(s):  
Tan Li ◽  
Jianzhuang Xiao
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Strain Curve ◽  
Confining Pressure ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Model ◽  
Large Size

Concrete made with large-size recycled aggregates is a new kind of recycled concrete, where the size of the recycled aggregate used is 25–80 mm, which is generally three times that of conventional aggregate. Thus, its composition and mechanical properties are different from that of conventional recycled concrete and can be applied in large-volume structures. In this study, recycled aggregate generated in two stages with randomly distributed gravels and mortar was used to replace the conventional recycled aggregate model, to observe the internal stress state and cracking of the large-size recycled aggregate. This paper also investigated the mechanical properties, such as the compressive strength, crack morphology, and stress–strain curve, of concrete with large-size recycled aggregates under different confining pressures and recycled aggregate incorporation ratios. Through this research, it was found that when compared with conventional concrete, under the confining pressure, the strength of large-size recycled aggregate concrete did not decrease significantly at the same stress state, moreover, the stiffness was increased. Confining pressure has a significant influence on the strength of large-size recycled aggregate cocrete.

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