Cristiana Ferreira

Dr. Cristiana Ferreira

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2016 in Journal of Materials in Civil Engineering
Verified
Journal Article
Open access
SRSara Rios
Sara Rios
NCNuno Cristelo
Nuno Cristelo
VFViana Da Fonseca
Viana Da Fonseca
CFCristiana Ferreira
Cristiana Ferreira
Alkaline activation of fly ash (FA) was used to improve the mechanical performance of a silty sand, considering this new material as a replacement for soil-cement applications, namely, bases and subbases, for transportation infrastructures. For that purpose, specimens were molded from mixtures of soil, FA, and an alkaline activator made from sodium hydroxide and sodium silicate. Uniaxial compression tests showed that strength is highly increased by the addition of this new binder. The results described a high stiffness material, with an initial volume reduction followed by significant dilation. All specimens have clearly reached the respective yield surface during shearing, and peak-strength Mohr–Coulomb parameters were defined for each mixture. The evolution of the microstructure during curing, responsible for the mechanical behavior detected in the previous tests, was observed by scanning electron microscopy. These results were compared with soil-cement data obtained previously with the same soi...

1 March 2009 in Geotechnical Testing Journal
Verified
Journal Article
Open access
VFViana Da Fonseca
Viana Da Fonseca
CFCristiana Ferreira
Cristiana Ferreira
MFMartin Fahey
Martin Fahey
Bender element (BE) testing is a powerful and increasingly common laboratory technique for determining the shear S-wave velocity of geomaterials. There are several advantages of BE testing, but there is no standard developed for the testing procedures or for the interpretation of the results. This leads to high degree of uncertainty and subjectivity in the interpretation. In this paper, the authors review the most common methods for the interpretation of BE tests, discuss some important technical requirements to minimize errors, and propose a practical framework for BE testing, based on the comparison of different interpretation techniques in order to obtain the most reliable value for the travel time. This new procedure consists of the application of a methodical, systematic, and objective approach for the interpretation of the results, in the time and frequency domains. The use of an automated tool enables unbiased information to be obtained regarding variations in the results to assist in the decision of the travel time. Two natural soils were tested: residual soil from Porto granite, and Toyoura sand. Specimens were subjected to the same isotropic stress conditions and the results obtained provided insights on the effects of soil type and confining stress on the interpretation of BE results; namely, the differences in testing dry versus saturated soils, and in testing uniform versus well-graded soils.

1 March 2017 in International Journal of Geomechanics
Verified
Journal Article
Open access
SRSara Rios
Sara Rios
NCNuno Cristelo
Nuno Cristelo
VFViana Da Fonseca
Viana Da Fonseca
CFCristiana Ferreira
Cristiana Ferreira
Alkaline activation of fly ash creates a geopolymeric cement that can replace ordinary portland cement in several applications such as soil improvement, with the advantage of much lower carbon dioxide emissions and reusing an industrial by-product otherwise landfilled, which averts several environmental problems. In this paper, the behavior of a silty sand improved by the alkaline activation of fly ash is analyzed from small to large strains by presenting uniaxial and drained triaxial compression test results and seismic wave velocities measured throughout the curing period. The dynamic, cyclic, and static tests showed a significant increase in stiffness with curing time, even beyond the 28-day curing period. On the basis of the nondestructive wave-propagation technique, the increase of the shear and compression wave velocities with time were drawn, giving the evolution of the elastic shear modulus and the Poisson ratio values. The dynamic Young modulus was compared to the correspondent secant You...

1 October 2006 in Geotechnical and Geological Engineering
Verified
Journal Article
Closed access
PDF file
VFViana Da Fonseca
Viana Da Fonseca
JCJ. Carvalho
J. Carvalho
CFCristiana Ferreira
Cristiana Ferreira
JSJ. A. Santos
J. A. Santos
FAFernando Almeida
Fernando Almeida
AOA. Oliveira
A. Oliveira

1 April 2007 in Soils and Foundations
Verified
Journal Article
Closed access
NCNilo Cesar Consoli
Nilo Cesar Consoli
KHKarla Salvagni Heineck
Karla Salvagni Heineck
MCMatthew Richard Coop
Matthew Richard Coop
VFViana Da Fonseca
Viana Da Fonseca
CFCristiana Ferreira
Cristiana Ferreira

1 August 2011 in Soils and Foundations
Verified
Journal Article
Closed access
CFCristiana Ferreira
Cristiana Ferreira
VFViana Da Fonseca
Viana Da Fonseca
DNDavid F.T. Nash
David F.T. Nash