Matric Suction Prediction Model in New AASHTO Mechanistic–Empirical Pavement Design Guide

Zapata, Claudia E.; Perera, Y. Y.; Houston, William N.

doi:10.3141/2101-07

Cited by 45 publications

(14 citation statements)

References 8 publications

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“…In addition, desiccation will shift the behaviour of lime-treated soil further within the framework of unsaturated soil mechanics. Therefore, it is imperative to account for the combined effects of cementation and environmental factors in the design of lime-treated expansive pavement subgrade (Zapata, 2009;Zapata, Andrei, Witczak, & Houston, 2007). The experimental database lacks information regarding the mechanical behaviour of lime-treated soils cured under different environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

The effect of curing conditions on the unconfined compression strength of lime-treated expansive soils

Elkady

2015

Road Materials and Pavement Design

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Unconfined compressive strength (UCS) is one of the main design parameters for flexible pavement and earthwork construction. During the design phase of lime-treated expansive subgrade, compacted specimens of different lime-soil mixtures are prepared and tested for UCS after being cured under controlled temperature and a high-humidity environment. During the field application of lime treatment, the curing conditions are far from been controlled especially in arid and semi-arid climates. This study aims at investigating the effect of different curing environments on the UCS of lime-treated expansive clays. Specifically, the study aims to assess the contribution of suction and cementation to the gain in UCS. Tests were conducted on expansive clays originated from two areas in Kingdom of Saudi Arabia (KSA). Remoulded specimens of lime-treated expansive clays with lime contents of 2%, 4%, and 6% (of dry weight basis) were cured under different curing environments; namely, normal curing (NC) (i.e. controlled temperature and high humidity environment), in-laboratory curing (ILC), and out-laboratory curing (OC) conditions. Curing periods considered were 7, 14, and 28 days. The main characteristics of ILC and OC environments evaluated based on continuous logging of climatic data (i.e. temperature and relative humidity) indicated low relative humidity which is a main characteristic of semi-arid and arid climates. For all curing environments, there is an observed increase in UCS with curing period, with maximum UCS values observed for OCcured specimens. Furthermore, the soil water characteristic curves of lime-treated specimens under different curing periods and lime content were evaluated to assess suction in specimens at the end of selected curing periods. Test results indicated that the gain in UCS for specimens cured under NC conditions is mainly attributed to an increase in cementation bonds. On the other hand, both ILC and OC environments promote the development of suction stresses that is a significant contributor to the gain in UCS as compared to cementation bonds.

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Section: Introductionmentioning

confidence: 99%

The effect of curing conditions on the unconfined compression strength of lime-treated expansive soils

Elkady

2015

Road Materials and Pavement Design

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“…However, this moisture content will change to a natural equilibrium state that is greatly dependent on environmental conditions, material properties and the groundwater table level. In a study that was carried out by Zapata et al (2009) Figure 1 is based on in situ measurements from two moisture rods, each consisting of four moisture probes (Salour and Erlingsson, 2013b). The moisture probes were installed at four different depths, with three of them located in the subgrade.…”

Section: Moisture In Pavement Unbound Materialsmentioning

confidence: 99%

Modelling resilient modulus seasonal variation of silty sand subgrade soils with matric suction control

2014

Self Cite

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Resilient modulus of unbound materials is an important parameter in the mechanistic design of pavements. Although unbound layers are frequently in a partially saturated state, a total stress approach is conventionally used in modelling the material behaviour and therefore pore pressure effects are not considered. In fine-grained unbound materials, the saturation state can affect their mechanical behaviour due to pore pressure effects. In this study a modified test procedure and a predictive resilient modulus model that takes into account the subgrade soil matric suction as a stress state variable is presented. Two different silty sand subgrade materials were tested in unsaturated conditions using series of repeated load triaxial tests under controlled pore suction conditions to study its influence on the resilient modulus. The test data were further used to obtain the resilient modulus model regression parameters that accounts for moisture content variations through the matric suction parameter. Generally, the prediction model could effectively capture the resilient modulus behaviour of the subgrades with respect to changes in the normal stress state and the matric suction. Given the completeness of this method, this prediction model is recommended as an improved approach in capturing the moisture content effects on the material stiffness properties.

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“…for some parameters a, b, and c. This formula has been experimentally confirmed for a wide range of values of the water content θ; see, e.g., [5,12,18]. At present (2020), this formula -with a minor modification that we will discuss later -is recommended by the US standards; see, e.g., p. 209 of Appendix DD1 "Resilient Modulus as Function of Soil Moisture -Summary of Predictive Models" of [10] and Chapter 5, p. 42 of [9] (see also Section 2.3 of [1]).…”

Section: Formulation Of the Problemmentioning

confidence: 60%

Scale-Invariance Ideas Explain the Empirical Soil-Water Characteristic Curve

Velasquez

Kreinovich

2020

2020 IEEE Symposium Series on Computational Intelligence (SSCI)

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The prediction of the road's properties under the influence of water infiltration is important for pavement design and management. Traditionally, this prediction heavily relied on expert estimates. In the last decades, complex empirical formulas have been proposed to capture the expert's intuition in estimating the effect of water infiltration on the stiffness of the pavement's payers. Of special importance is the effect of water intrusion on the pavement's foundation-known as subgrade soil. In this paper, we show that natural scale-invariance ideas lead to a theoretical explanation for an empirical formula describing the dependence between soil suction and water content; formulas describing this dependence are known as soil-water characteristic curves.

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Matric Suction Prediction Model in New AASHTO Mechanistic–Empirical Pavement Design Guide

Cited by 45 publications

References 8 publications

The effect of curing conditions on the unconfined compression strength of lime-treated expansive soils

The effect of curing conditions on the unconfined compression strength of lime-treated expansive soils

Modelling resilient modulus seasonal variation of silty sand subgrade soils with matric suction control

Scale-Invariance Ideas Explain the Empirical Soil-Water Characteristic Curve

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