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ANALYISIS OF MECHANICAL PROPERTIES OF CONCRETE CONTAINING FLY ASH AND NANOSILICA
Silvia T. Esteves (1), Hildélix Soto (1), O. Marcelo Suárez (2)
(1) University of Puerto Rico Mayagüez, Civil Engineering and Surveying Department
(2) University of Puerto Rico Mayagüez, General Engineering Department
Environmental protection is a major concern in the construction industry nowadays. For instance, in concrete manufacturing fly ash is a repurposed industrial waste. Unfortunately, fly ash decreases the rate of strengthening in concrete at early age due to a resulting slower reaction. Hence, the main focus of this research has been to design a high strength concrete using fly ash and nanostructured silica (nS). Nanosilica is used to counter balance the strength loss due to the addition of fly ash, used as partial replacement of cement. The use of nS in the construction industry is not yet common, causing that the mechanical properties of concrete with these partial replacements are not fully understood. Compressive strength, tensile strength, flexural, absorption, and permeability tests were performed at an age of 7, 28, and 90 days of curing of concrete containing fly ash and nS. In the present research, concrete microstructure and overall strength was found to be improved by adding nS. Future work will focus on further understanding other mechanical properties such as hardness, creep deformation, fatigue, and durability. This work was made possible with the support of the National Science Foundation under grant number HRD 1345156 (CREST program).
O. Marcelo Suárez