Influence of Nanofibrillated Cellulose (NFC) on the Mechanics of Cement Pastes: Fid-Bau Portal

Influence of Nanofibrillated Cellulose (NFC) on the Mechanics of Cement Pastes

de Souza, Letícia O. / Souza, Lourdes M. S. / Silva, Flávio A.

The use of nanomaterials in several fields has been growing in the past few years due to their unique physical and mechanical properties. Nevertheless, the use of these materials in civil engineering is fairly new and still requires extensive research to completely understand their potential. The search and development of new cementitious materials that are less harmful to the environment are significantly important. In this scenario, the nanocellulose comes as an interesting option of reinforcement for cementitious elements. One of the constraints of the more intensive employment of nanomaterials is the formation of agglomerates that act as defects and stress concentrators in the elements. In this way, the development of efficient dispersion techniques is essential for the total exploitation of the mechanical properties of the nanomaterials, including the nanocellulose. In the present research, nanofibrillated cellulose (NFC) obtained from Eucalyptus pulp fiber was added into cement pastes thin elements in several contents. The mechanical behavior was assessed by means of four-point bending tests. The percentage of NFC varied between 0 and 1% of the mass of cement. In an attempt to explore most of the properties of NFC and then enhance the mechanical properties of the composites, dispersion strategies were applied as a step on the mixture procedure. Chemical dispersion methods were combined with mechanical stirring in order to produce a homogenous solution of water and NFC. Results showed expressive improvements regarding mechanical properties upon the addition of NFC on the cement pastes. The flexural strength enhanced by more than 400%, and the flexural modulus more than 13 times. Results also indicated that the dispersion methods applied were able to influence positively the flexural strength, and this improvement is sensible to the content of NFC.