The main objective of this paper is study the influence

\r\nof carbon nano-tubes fibers and nano silica fibers on the

\r\ncharacteristic compressive strength and flexural strength on concrete

\r\nand cement mortar. Twelve tested specimens were tested with square

\r\nsection its dimensions (40\uf0b440 \uf0b4160) mm, divided into four groups.

\r\nThe first and second group studied the effect of carbon nano-tubes

\r\n(CNTs) fibers with different percentage equal to 0.0, 0.11%, 0.22%,

\r\nand 0.33% by weight of cement and effect of nano-silica (nS) fibers

\r\nwith different percentages equal to 0.0, 1.0%, 2.0%, and 3.0% by

\r\nweight of cement on the cement mortar. The third and fourth groups

\r\nstudied the effect of CNTs fiber with different percentage equal to

\r\n0.0%, 0.11%, and 0.22% by weight of cement, and effect of nS fibers

\r\nwith different percentages were equal to 0.0%, 1.0%, and 2.0% by

\r\nweight of cement on the concrete. The compressive strength and

\r\nflexural strength at 7, 28, and 90 days is determined. From analysis of

\r\ntested results concluded that the nano-fibers is more effective when

\r\nused with cement mortar more than used with concrete because of

\r\nincreasing the surface area, decreasing the pore and the collection of

\r\nnano-fibers. And also by adding nano-fibers the improvement of

\r\nflexural strength of concrete and cement mortar is more than

\r\nimprovement of compressive strength.<\/p>\r\n","references":"[1] Quercia G., and Brouwers H. J. H, \u201cApplication of nanosilica (nS) in\r\nconcrete mixtures,\u201d8th fib PhD Symposium inKgs. Lyngby, Denmark,\r\n2010, p.6.\r\n[2] Plassard, C, Lesniewska, E, Pochard, I, Nonat, A.,\u201d Investigation of the\r\nsurface structure and elastic properties of calcium silicate hydrates at the\r\nnano-scale,\u201d Ultramicroscopyvol.100, no.3-4, 2005, pp. 331-338.\r\n[3] Porro, A., Dolado, J.S., Campillo, I., Erkizia, E., de Miguel, Y.,S\u00e1ez de\r\nIbarra, Y., Ayuela, A., \u201cEffects of nano-silica additions on cement\r\npastes; Applications of nanotechnology in concrete design,\u201d Thomas\r\nTelford; London, 2005.\r\n[4] Ismael flores-vivian, Rani G.K. Pradoto, Mohamad rezamoini,\r\nKonstantin sobolev, \u201cthe use of nanoparticles to improve the\r\nperformance of concrete,\u201dBrno, Czech Republic, EU, vol.10, 2013,pp.\r\n16 -18.\r\n[5] Collepardi, M., Ogoumah-Olagot, J.J., Skarp, U., Troli, R., \u201cInfluence of\r\namorphous colloidal silica on the properties of self-compacting\r\nconcretes,\u201d Proceedings of the International Conference, Dundee, UK,\r\n2002, pp. 473 - 483.\r\n[6] Chan L. Y. and Andrews B., \u201cFinite element analysis of carbon\r\nnanotube\/cement composite with degraded bond strength,\u201d\r\nComputational Materials Science, vol.47,no.4, 2010, pp.994-1004.\r\n[7] Metaxa Z. S., and et al., \u201cCarbon nano reinforced concrete,\u201d ACI Special\r\nPublications Nanotechnology of Concrete The Next Big Thing is Small\r\nSP, vol. 267, no. 2, 2009, pp.11-20.\r\n[8] Ata El-kareim Shoeib, \u201cEffect of nanotube carbon fibers in fracture\r\nmechanics of reinforced concrete structure, \"Fifth International\r\nConference on nano-technology in construction (NTC 2013), 2013, p.9.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 97, 2015"}