Sustainable Air-Entrained Concrete with Partial Replacement of Fly Ash and Nanostructured Silica

Undergraduate #376
Discipline: Technology and Engineering
Subcategory: Materials Science

Marivette Rullan~Semidey - University of Puerto Rico, Mayaguez
Co-Author(s): Carlos Medina, Hildélix Soto, O. Marcelo Suárez, Raul E. Marrero, Andres Matos, Fernando Benitez, Silvia T. Esteves, and Maria Sepulveda, University of Puerto Rico, Mayaguez Campus

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The addition of aluminum in concrete mixtures is known to produce air-entrained concrete through the formation of spherical pores in the material. This is ideal for cold regions, because it allows water retained in concrete to expand when it freezes. As the water expansion is contained within those pores, the concrete integrity is not compromised. Alas, those micropores compromise the mechanical strength of the material since they act as stress concentration sites. The purpose of this research is to develop an air-entrained concrete where such lower mechanical performance can be counteracted by the addition of silica nanoparticles and fly ash. Mixes where contrived with 0.005%, 0.01% and 0.02% of aluminum powder to follow the parameters currently used by the industry. Naturally, the compressive strength preliminary results showed a strength reduction as the aluminum amount increased. Similar behavior was found upon tensile strength tests. The research work is in course: complementary compressive, tensile and flexural strength tests are programed to be completed this semester. The results will be compared with previous research of high performance concrete with no aluminum incorporated. The ultimate goal is to produce an air entrained concrete with better structural capacity for sustainable construction applications.

Funder Acknowledgement(s): This material is based upon work supported by the National Science Foundation under Grant No. 1345156 (CREST program).

Faculty Advisor: O. Marcelo Suárez, msuarez@ece.uprm.edu