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Tungsten mine waste geopolymeric binder : preliminary hydration products invest...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidGeopolymeric mine waste mud (GMWM) binders are obtained from dehydroxylated waste powder mixed with minor quantities of calcium hydroxide, activated with NaOH and waterglass solutions. In this work recent investigations of GMWM binders hydration products have been carried out. The hydration products have been investigated by means of X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spe...
Utilization of mining wastes to produce geopolymer binders
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidThis chapter discusses de utilization of mining wastes to produce geopolymeric binders. It includes the influence of calcination operations in the reactivity of mine wastes; in what way mix design parameters influence strength gain; it covers physical and mechanical properties and also durability and environmental performance.
Adhesion characterization of tungsten mine waste geopolymeric binder. Influence...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidTungsten mine waste mud (TMWM) was investigated for its potential use as repair material of ordinary portland cement (OPC) concrete. Bond strength between OPC concrete substrate and three repair materials was analysed. TMWM geopolymeric binder and two commercial repair products were used as repair materials. Bond strength behaviour was assessed from slant shear tests. A total of 128 slant shear specimens were m...
Properties of tungsten mine waste geopolymeric binder
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidTungsten mine waste mud (TMWM) geopolymeric binder is a new cementitious material with a very high early age strength. It is obtained from dehydroxylated mine waste powder mix with minor quantities of calcium hydroxide and activated with NaOH and water-glass solutions. Tests on properties of TMWM binders such as workability, setting time, unrestrained shrinkage, water absorption and static modulus of elasticity...
Investigations on mix design of tungsten mine waste geopolymeric binder
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidStrength data show that the parameters, which lead to optimum strength for 7 days curing, remain the same for long curing ages. However, when calcium hydroxide percentages above 10% are used, strength decrease after 14th curing day is noticed. In order to explain this behaviour several hypotheses are discussed. The use of an activator with a sodium hydroxide concentration of 24 M leads to a compressive strength...
Alkali-activated binders : a review : part 2. about materials and binders manuf...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidThis paper summarizes current knowledge about alkali-activated binders, by reviewing previously published work. As it is shown in Part 1, alkali-activated binders have emerged as an alternative to (ordinary Portland cement) OPC binders, which seem to have superior durability and environmental impact. The subjects of Part 2 of this paper are prime materials, alkaline activators, additives, curing type and consti...
Alkali – activated binders: a review part 1. Historical background, terminology...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidThe disintegration of concrete structures made of ordinary Portland cement (OPC) is a worrying topic of increasing significance. The development of new binders with longer durability is therefore needed. Alkali-activated binders have emerged as an alternative to OPC binders, which seems to have superior durability and environmental impact. This paper reviews current knowledge about alkali-activated binders. The...
Investigations of tungsten mine waste geopolymeric binder : strength and micros...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidThis paper reports some results of a research project related to the development of a new binder using mineral waste mud from the Portuguese mine. Some aspects related to the effect of aggregates in the microstructure and mechanical behaviour of tungsten mine waste geopolymeric binder are reported in the present study. Test results showed that the aggregate type influences strength development.
Ligantes obtidos por activação alcalina de lamas residuais das Minas da Panasqu...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidEste artigo apresenta alguns resultados sobre resistência ao desgaste e ao ataque em meio ácido de argamassas obtidas por activação alcalina de lamas residuais das Minas da Panasqueira (AALRM). Para efeitos de comparação procedeu-se também à avaliação da mesma resistência em betões correntes das classes (C20/25 e C30/37). A resistência ao desgaste foi avaliada através da perda de massa dos provetes quando subme...
Ligantes activados alcalinamente : reactividade de lamas residuais de minas apó...
Torgal, Fernando Pacheco; Gomes, J. P. Castro; Jalali, SaidO cimento Portland é em termos mundiais, o material mais utilizado na industria da construção, sendo simultaneamente responsável por um elevado nivel de emissões de CO2 (1 ton of cimento gera 1 ton. de CO2). O seu uso tende por isso a ser cada vez menos competitivo quando comparado com novos ligantes mais amigos do ambiente, como os ligantes obtidos pela activação alcalina de sub-produtos industriais (cinzas vo...
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