Crushed rocks stabilized with organosilane and lignosulfonate in pavement unbound layers: Repeated load triaxial tests

This paper presents the findings of a laboratory investigation on the characterization of recycled crushed brick when blended with recycled concrete aggregate and crushed rock for pavement sub-base applications. The engineering properties of the crushed brick blends were compared with typical state road authority specifications in Australia for pavement sub-base systems to ascertain the potential use of crushed brick blends in these applications. The experimental programme included particle-size distribution, modified Proctor compaction, particle density, water absorption, California bearing ratio (CBR), Los Angeles abrasion, pH, organic content, and repeated load triaxial tests. Laboratory tests were undertaken on mixtures of 10%, 15%, 20%, 25%, 30%, 40%, and 50% crushed brick blended with recycled concrete aggregate or crushed rock. The research indicates that up to 25% crushed brick could be safely added to recycled concrete aggregate and crushed rock blends in pavement sub-base applications. The repeated load triaxial test results on the blends indicate that the effects of crushed brick content on the mechanical properties in terms of permanent deformation and resilient modulus of both the recycled concrete aggregate and crushed rock blends were marginal compared to the effects on dry density and moisture content.

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Neural Network Modeling of Anisotropic Aggregate Behavior from Repeated Load Triaxial Tests

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1615-12 ◽

1998 ◽

Vol 1615 (1) ◽

pp. 86-93 ◽

Cited By ~ 19

Author(s):

Erol Tutumluer ◽

Umit Seyhan

Keyword(s):

Neural Networks ◽

Triaxial Tests ◽

Neural Network Modeling ◽

Dry Density ◽

Prediction Ability ◽

Aggregate Properties ◽

Target Values ◽

Ann Models ◽

Repeated Load ◽

Repeated Load Triaxial

Determining horizontal specimen response in a repeated load triaxial test is essential to properly characterize the directional dependency of unbound aggregate resilient behavior under anisotropic loading conditions. Recent research has applied artificial neural networks (ANNs) for predicting, in the absence of lateral deformation data, the anisotropic stiffness properties of granular materials from standard AASHTO tests. Feed-forward backpropagation-type neural networks were successfully trained with two triaxial stresses (confining pressure and applied deviator stress), measured vertical deformation, and two aggregate properties (compacted dry density and crushed particle percentage) used as input variables. The output variables were the horizontal and shear moduli for which the actual (target) values were derived and computed from test results. The ANN models predicted the two moduli, with mean errors of less than 3 percent compared with those computed by using experimental stresses and strains. Both the applied stress state and the aggregate properties were found to affect the generalization and thus the prediction ability of the ANN models.

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Geogrid Stabilization of Unbound Aggregates Evaluated Through Bender Element Shear Wave Measurement in Repeated Load Triaxial Testing

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198120908230 ◽

2020 ◽

Vol 2674 (3) ◽

pp. 113-125

Author(s):

Mingu Kang ◽

Joon Han Kim ◽

Issam I. A. Qamhia ◽

Erol Tutumluer ◽

Mark H. Wayne

Keyword(s):

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Resilient Modulus ◽

Triaxial Tests ◽

Triaxial Testing ◽

Bender Element ◽

Wave Measurement ◽

Repeated Load ◽

Repeated Load Triaxial

This paper describes the use of the bender element (BE) shear wave measurement technology for quantifying the effectiveness of geogrid stabilization of unbound aggregate materials with improved mechanical properties from repeated load triaxial testing. Crushed stone aggregate specimens were prepared with three different gradations, that is, upper bound (UB), mid-range engineered (ENG), and lower bound, according to the dense graded base course gradation specification in Illinois. The specimens were compacted at modified Proctor maximum dry densities and optimum moisture contents. Two geogrids with different triaxial aperture sizes were placed at specimen mid-height, and unstabilized specimens with no geogrid were also prepared for comparison. To measure shear wave velocity, three BE pairs were placed at different heights above geogrid. Repeated load triaxial tests were conducted following the AASHTO T307 standard resilient modulus test procedure, while shear wave velocity was measured from the installed BE pairs. After initial specimen conditioning, and at low, intermediate, and high applied stress states, both the resilient moduli and accumulated permanent strains were determined to relate to the geogrid local stiffening effects in the specimens quantified by the measured shear wave velocities. The resilient modulus and shear wave velocity trends exhibited a directly proportional relationship, whereas permanent strain and shear wave velocity values were inversely related. The enhancement ratios calculated for the geogrid stabilized over the unstabilized specimens showed significant improvements in mechanical behavior for the UB and ENG gradations, and a maximum enhancement was achieved for the engineered gradation specimens stabilized with the smaller aperture geogrid.

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Resilient Moduli of Treated Clays from Repeated Load Triaxial Test

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1821-08 ◽

2003 ◽

Vol 1821 (1) ◽

pp. 68-74 ◽

Cited By ~ 12

Author(s):

Anand J. Puppala ◽

Aravinda M. Ramakrishna ◽

Laureano R. Hoyos

Keyword(s):

Clayey Soil ◽

Resilient Modulus ◽

Triaxial Tests ◽

Cement Type ◽

Repeated Load ◽

Resilient Response ◽

Type V ◽

Deviatoric Stresses ◽

The Impact ◽

Repeated Load Triaxial

Three chemical stabilization methods—sulfate resistant cement (Type V), low-calcium fly-ash (Class F) mixed with sulfate resistant cement (Type V), and ground granulated blast furnace slag—were used in a series of repeated load triaxial tests on clayey soil to assess the effectiveness of these three stabilizers in enhancing resilient modulus ( MR) properties of the soil. MR results were measured from repeated load triaxial tests conducted on both control and treated soils at optimum moisture content levels. Test results were analyzed to understand the potentials of each stabilizer on MR response of the soils and to study the effects of confining and deviatoric stresses on resilient response of the treated soils. Mechanisms for MR enhancements in treated soils were developed, and a series of flexible pavement design exercises was conducted to evaluate the impact of each stabilizer on the design thickness of the asphalt surface layer of pavements.

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Using Repeated-Load Triaxial Tests to Evaluate Plastic Strain Potentials in Subgrade Soils

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198105191300109 ◽

2005 ◽

Vol 1913 (1) ◽

pp. 86-98 ◽

Cited By ~ 7

Author(s):

Anand J. Puppala ◽

Suppakit Chomtid ◽

Venkat Bhadriraju

Keyword(s):

Plastic Strain ◽

Test Procedure ◽

Soil Layer ◽

Silty Sand ◽

Triaxial Tests ◽

Plastic Strains ◽

Plastic Deformations ◽

Subgrade Soils ◽

Repeated Load ◽

Repeated Load Triaxial

The design and the analysis of flexible pavement systems depend on soil layer characterization, traffic loads, and number of passes. The current AASHTO design method for flexible pavements uses resilient characteristics of subsoils to characterize and determine the structural support of each layer and to design the thickness of the layers. This moduli property, however, does not fully account for the plastic strain or rutting potentials of subsoils, as in the cases in which silt and mixed soils undergo high plastic deformations but possess high resilient properties. A study was initiated to establish a test procedure to use a repeated load triaxial device to measure plastic strain potentials of subgrade soils. Laboratory-compacted soil specimens were subjected to a repeated deviatoric load, determined as a percentage of static deviatoric load at failure under un-consolidated undrained conditions. The plastic strains were monitored during 10,000 repeated load cycles, and the accumulated plastic deformations were determined. The test procedure and test results conducted on two types of soils, a coarse sand and silty sand, are presented. Effects of soil type, compaction moisture content, dry unit weight, confining pressure, and deviatoric stresses on the plastic strains were addressed.

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