Civil Engineering Materials

Civil Engineering Materials prepares you for today’s engineering challenges, providing a broad overview of the materials you will use in your studies and career. You are not only introduced to traditional materials, such as concrete, steel, timber, and soils, but you also explore important non-traditional materials, such as synthetics and industrial-by products. The authors use a wealth of practical examples and straight-forward explanations to ensure you gain a full understanding of the characteristics and behavior of various materials, how they interact, and how to best utilize and combine traditional and non-traditional materials. While emphasizing the effective use of civil engineering materials, the authors carefully consider sustainability to give you a broader context of how materials are current used in contemporary applications

Determination of fatigue life of a granular base material lightly stabilized with slag lime from indirect diametral tensile testing

Stabilization of granular materials with low percentage of slow setting binders, such as slag lime, for constructing new pavements and/or rehabilitation of existing granular pavements has economical and environmental benefits. The fatigue life of a lightly stabilized granular material under traffic type repeated or cyclic loading is an important consideration for pavement design involving this material and it is the focus of this paper. In particular, this paper examines the use of indirect diametrical tensile IDT testing with internal displacement measurement for determining stiffness and fatigue life of a granular base material lightly stabilized with slag-lime cementitious binder. An extensive laboratory investigation involving monotonic and cyclic load IDT testing was carried out to determine the strength, stiffness, and fatigue life of a granular material stabilized lightly with 3& 8211;5% slag lime and to establish relationships for predicting the fatigue life. Fatigue life was established using two methods, namely, the approach of determining the number of cycles for 50% reduction in the stiffness compared to the initial stiffness and the energy ratio method, and they both showed similar results. Based on the experimental results, a general fatigue model is proposed for determining the fatigue life using the static or dynamic stiffness modulus and maximum tensile strain, which is useful for mechanistic-empirical pavement design involving such materials. Empirical equations are proposed to relate the fatigue life with tensile strain and stress ratio similar to those proposed in the literature. A new model to determine the fatigue life from strain ratio is also proposed in this paper that was found to closely match the experimental data. Empirical relationships are also proposed to predict the fatigue life based on IDT strength and/or static stiffness modulus which are particularly useful in situations where resources are not available for conducting cyclic load IDT testing

Determining the characteristics of recycled aggregate from pavement model testing

Characteristics of a recycled aggregate for pavement design were studied from pavement model (PM) testing under sinusoidal type vertical cyclic loading through a 184 mm diameter steel plate. The PM tests were conducted in a steel tank having the inside dimensions of 1.00 m x 1.10 m in plan and 0.6 m height. Innovative instrumentation techniques were used to measure the vertical deformations and horizontal strains at different depths to determine the characteristics of the recycled aggregate. Details of the experimental setup, instrumentation and typical results on the stiffness and accumulation of permanent deformation needed for pavement design are discussed

Fatigue Behaviour of Lightly Stabilised Granular Materials from Flexural and Indirect Diametral Tensile Testing

The fatigue characteristic of a lightly stabilized granular material under traffic loading is an important consideration for the design of a pavement containing such material. This paper presents the evaluation of fatigue behavior of lightly stabilised granular materials using flexural and indirect diametral tensile (IDT) testing. The experimental program included cyclic load flexural and IDT testing to determine the fatigue life of a typical granular material stabilized lightly with 1-3% cement-flyash. Fatigue life was estimated using the approach of approximate energy ratio method and empirical relationships were proposed to relate the fatigue life with tensile strain similar to that proposed in the literature. Details of the experimental investigation, the analysis carried out to determine the fatigue life of the lightly stabilized granular material and comparisons of fatigue characteristics determined from two test methods are discussed in the paper. ASCE.Scopu

Characterization of lightly stabilized granular base materials using monotonic and cyclic load flexural testing

Lightly cementitiously stabilized granular materials are generally characterized by their tensile properties and this paper examines the use of monotonic and cyclic load flexural testing to determine the tensile characteristics of these materials. The research reported in this paper included the determination of modulus of rupture as well as static and dynamic stiffness moduli from monotonic and cyclic load flexural testing for two typical freshly quarried granular base materials stabilized by the addition of 1-3% cement-fly ash slow-setting binder. A flexural testing setup with improved deformation measurement was developed and the tests were conducted on 28-day cured samples prepared by static compaction. Details of improved flexural testing arrangement with on-sample midspan deflection measurement for performing monotonic and cyclic load testing to obtain reliable data are also discussed. The research reported in this paper indicates that cyclic load flexural testing could be used reliably for determining the dynamic stiffness modulus of a lightly stabilized granular material. Correlations among the mechanical properties obtained from flexural testing are also presented. 2015 American Society of Civil Engineers.Scopu

Interpretation of Cone Penetration Test Data of an Embankment for Coupled Numerical Modeling

The Nerang Broadbeach Roadway (NBR) embankment in Australia is founded on soft clay deposits. The embankment sections were preloaded and surcharged-preloaded to limit the post-construction deformation and to avoid stability failure. In this paper, we discuss the NBR embankment’s geology, geotechnical properties of the subsurface, and long-term field monitoring data from settlement plates and piezometers. We demonstrate a comparison of cone penetration test (CPT) and piezo cone dissipation test (CPT-u) interpreted geotechnical properties and the NBR embankment’s foundation stratification with laboratory and field measured data. We also developed two elasto-viscoplastic (EVP) models for long-term performance prediction of the NBR embankment. In this regard, we considered both the associated and the non-associated flow rule in the EVP model formulation to assess the flow rule effect of soft clay. We also compared EVP model predictions with the Modified Cam Clay (MCC) model to evaluate the effect of viscous behavior of natural Estuarine clay. Both EVP models require six parameters, and five of them are similar to the MCC model. We used the secondary compression index of clay in the EVP model formulations to include the viscous response of clay. We obtained numerical models’ parameters from laboratory tests and interpretation of CPT and CPTu data. We observed that the EVP models predicted well compared with the MCC model because of the inclusion of soft clay’s viscosity in the EVP models. Moreover, the flow rule effect in the embankment’s performance predictions was noticeable. The non-associated flow rule EVP model predicted the field monitoring settlement and pore pressure better compared to the MCC model and the associated flow EVP model

Finite Element Simulations of an Elasto-Viscoplastic Model for Clay

In this paper, we develop an elasto-viscoplastic (EVP) model for clay using the non-associated flow rule. This is accomplished by using a modified form of the Perzyna’s overstressed EVP theory, the critical state soil mechanics, and the multi-surface theory. The new model includes six parameters, five of which are identical to those in the critical state soil mechanics model. The other parameter is the generalized nonlinear secondary compression index. The EVP model was implemented in a nonlinear coupled consolidated code using a finite-element numerical algorithm (AFENA). We then tested the model for different clays, such as the Osaka clay, the San Francisco Bay Mud clay, the Kaolin clay, and the Hong Kong Marine Deposit clay. The numerical results show good agreement with the experimental data

Determination of Stiffness Modulus and Poisson's Ratio of Lightly Stabilized Granular Materials From Indirect Diametral Tensile Testing

Lightly cementitiously stabilized granular materials are generally characterised by their tensile properties that are required for the analysis and design of a pavement structure involving these materials. Tensile properties include tensile strength, stiffness modulus, and Poisson's ratio. However, there are limited studies on the mechanistic determination of stiffness modulus and Poisson's ratio of lightly stabilized materials; rather, a magnitude of Poisson's ratio is often assumed. This paper examines the use of monotonic and cyclic load indirect diametral tensile (IDT) testing to determine the Poisson's ratio and stiffness modulus of lightly stabilized granular materials. The experimental program included the determination of IDT strength, static and dynamic stiffness modulus, and Poisson's ratio for a typical freshly quarried granular base material stabilized by the addition of 0.5 to 3 % cement-flyash and 1.5 to 3 % slag-lime slow-setting binder. A new IDT testing setup to measure both the horizontal and vertical deformations along the diameters of an IDT specimen was developed and the tests were conducted on 28 days cured samples prepared by gyratory compaction. Details of the new IDT testing arrangement with on-sample deformation measurement for performing monotonic and cyclic load testing to obtain reliable data are discussed. This study indicates that the proposed IDT testing setup with on-sample deformation measurement could be used reliably for determining the tensile properties of lightly stabilized granular materials including the Poisson's ratio.Scopu