Guzmán-Durán, Danel

Profile Picture

Filters

20121
Reset filters

Settings

Citations

Publication Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Publication
    Estudio de la influencia de las adiciones minerales como sustituto parcial del cemento Portland en las propiedades mecánicas y de durabilidad del hormigón
    (2012) Guzmán-Durán, Danel; Molina-Bas, Omar I.; College of Engineering; González Quevedo, Antonio A.; Acosta Costa, Felipe J.; Department of Civil Engineering; Cedeño, José R.
    The use of mineral admixtures as substitute of cement in concrete is widely extended for various reasons. The reduction of doses of cement in the concrete mixtures reduces the material costs, decreases the pollution and helps solve the problem of the elimination of the "byproducts". Moreover, the microstructural changes motivated by the mineral admixtures should generate a more compact concrete and a reduction in the average size of the pores. This can contribute to the improvement of the mechanical properties and durability of concrete. The efficacy of the use of the mineral admixtures is complex, hard to generalize and depends on the availability of materials in the local markets. This is because of variations in the physical and chemical properties of the mineral admixtures and the cements employed despite their classification under the same standard. Due to these factors, the importance of the changes in composition and microstructure in the mechanical properties and the durability of the material are not completely clear. This work studies the influence of various mineral admixtures available in the local market of Puerto Rico and the Caribbean as a substitute for Portland cement: fly ash, slag, and volcanic ash, on the mechanical properties and durability of concrete to determine if the combination of these products helps to improve the concrete which is produced in the same. The substitution levels fluctuate between 12.5% and 25% of the cementations material, including combinations. Those resulting concretes have been mechanically characterized and its porous structure has been studied through mercury intrusion porosimetry. Moreover, its resistance was measured to the diffusion of aggressive agent, chloride ion. The results manifest the relevance of local adjustments in function of the properties in the admixtures and cements used. The use of fly ash type F as a partial replacement of 25% of Portland cement in concrete mixtures is one of the best options to optimize concrete mixtures in terms of mechanical properties and durability, if does not require high performance before 91 days of curing. If you require high performance at ages as young as 7 days of cure, employing blast furnace slag as a partial replacement of 25% of Portland cement is one of the best options. Volcanic ash from the island of Monserrat significantly improves the mechanical properties in terms of compressive strength. However, it contributes to, but in any case also worsens, the durability of the material in terms of chloride ion penetration. Confirming the investigators hypothesis that an improvement in the mechanical properties does not necessarily improve the durability. The use of combinations of mineral additions refines the pores of the concrete, increases the compressive strength values and the resistance to penetration of chloride ion compared to similar concretes not using minerals additions.