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Rita Gião

Bio: Rita Gião is an academic researcher from Polytechnic Institute of Lisbon. The author has contributed to research in topics: Grout & Beam (structure). The author has an hindex of 4, co-authored 8 publications receiving 74 citations. Previous affiliations of Rita Gião include Instituto Superior de Engenharia de Lisboa.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer was investigated.
Abstract: This paper deals with the coupled effect of temperature and silica fume addition on rheological, mechanical behaviour and porosity of grouts based on CEMI 42.5R, proportioned with a polycarboxylate-based high range water reducer. Preliminary tests were conducted to focus on the grout best able to fill a fibrous network since the goal of this study was to develop an optimized grout able to be injected in a mat of steel fibers for concrete strengthening. The grout composition was developed based on criteria for fresh state and hardened state properties. For a CEMI 42.5R based grout different high range water reducer dosages (0%, 0.2%, 0.4%, 0.5%, 0.7%) and silica fume (SF) dosages (0%, 2%, 4%) were tested (as replacement of cement by mass). Rheological measurements were used to investigate the effect of polycarboxylates (PCEs) and SF dosage on grout properties, particularly its workability loss, as the mix was to be injected in a matrix of steel fibers for concrete jacketing. The workability behaviour was characterized by the rheological parameters yield stress and plastic viscosity (for different grout temperatures and resting times), as well as the procedures of mini slump cone and funnel flow time. Then, further development focused only on the best grout compositions. The cement substitution by 2% of SF exhibited the best overall behaviour and was considered as the most promising compared to the others compositions tested. Concerning the fresh state analysis, a significant workability loss was detected if grout temperature increased above 35 °C. Below this temperature the grout presented a self-levelling behaviour and a life time equal to 45 min. In the hardened state, silica fumes increased not only the grout’s porosity but also the grout’s compressive strength at later ages, since the pozzolanic contribution to the compressive strength does not occur until 28 d and beyond.

54 citations

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TL;DR: In this article, an experimental campaign was carried out in order to assess the influence of the gravity load on RC beam connection to the column subjected to cyclic loading, and the results are compared and analyzed in this paper.

25 citations

Journal ArticleDOI
TL;DR: In this article, a high performance cementitious grout reinforced with continuous and unidirectional non-woven steel fibre mat has been developed for this purpose, where the optimization of the percentage and alignment of the steel fibres would yield a more efficient fibre grout.

10 citations

Journal ArticleDOI
TL;DR: In this article, a parametric analysis of the gravity load effects on the behavior of reinforced concrete beam critical zones when subjected to cyclic loads was carried out, and the results were analyzed in terms of global hysteretic response, accumulated energy dissipation and equivalent viscous damping ratio.

9 citations

01 Jan 2012
TL;DR: In this paper, a seismic conception of strong-column-weak-beam is proposed and the global structure response improvement can be attained through the strengthening of the beams in the beam-column connections.
Abstract: In a frame system, the seismic energy is mostly dissipated through the development of plastic hinges located, in general, at the extremities of the elements. Thus, admitting a seismic conception of strong-column–weak-beam, the global structure response improvement can be attained through the strengthening of the beams in the beam-column connections. This fact justifies the search for new RC beam-column connections solutions with high seismic performance.

5 citations


Cited by
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Journal ArticleDOI
Shucai Li1, Fei Sha1, Rentai Liu1, Qingsong Zhang1, Zhaofeng Li1 
TL;DR: In this article, the properties of six different MC grouts (three portland-based and three slag-blended) and two ordinary Portland cements (ASTM I and III) are measured.

45 citations

Journal ArticleDOI
TL;DR: In this article, the development of coated pellets as a self-healing system in cement-based materials was described, which was utilised for producing pellets from three different powder minerals as potential healing agents: reactive magnesium oxide (MgO), silica fume and bentonite.

38 citations

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TL;DR: It is important to choose grouting materials that are soft and fine enough to penetrate into the discontinuities in voids, cracks, or cavities to fill them to improve the mechanical properties and impermeability of a particular system.
Abstract: Grout is a binding agent or binder often used with building materials to improve their durability functions. It may be organic or inorganic material used for sealing or consolidation of cracks, pores, or voids in order to improve the mechanical properties and impermeability of a particular system, whether soil, cementitious or of other building materials. Grouts act as dispersion agents where dispersed particles form a network responsible for the effectiveness of grouting properties. Chemical grouts are the most common and well-known grouting materials used for sealing sand, soil, or other matrices. However, this is an expensive technique and it also affects the environment because chemical grouts based on acrylamides, lignosulfonates, and polyurethane are toxic and environmentally harmful. Thus, it is necessary to find new grouting materials and methods of injection. It is important to choose grouting materials that are soft and fine enough to penetrate into the discontinuities in voids, cracks, or cavities to fill them (Bras et al., 2013).

32 citations

Journal ArticleDOI
TL;DR: The abovementioned flaw is eliminated in this paper from the Menegotto and Pinto model and the improvement over the original model is shown by means of nonlinear dynamic analyses on simple reinforced concrete and steel frames.

30 citations

Journal ArticleDOI
TL;DR: In this article, the main effects of high water content on the microstructure and mechanical properties of the materials, looking at physical and chemical aspects, were investigated using scanning electron microscopy and chemical phase analysis.
Abstract: Geopolymers have gained much interest recently as a promising alternative to cementitious materials in some applications. However, research is still needed to use this technology for soil reinforcement grouts. The specifications of grouts mainly consist in rheological properties, strength and permeability. Grouting actually requires a low viscosity, and thus higher water content. The influence of relatively high water content on the other properties of the material, i.e. strength and microstructure, has been investigated. This effect highly depends on the concentration of the activator (sodium silicate solution) and the precursor (metakaolin, fly ash or blast furnace slag) associated with the activator. This paper deals with the main effects of high water content on the microstructure and mechanical properties of the materials, looking at physical and chemical aspects. Scanning electron microscopy and chemical phase analysis were used to highlight the nuances that are related to the precursors used, espec...

28 citations