Nano Graduate School (NGS-NANO) Meeting Sep. 10 Lammi Prasantha R. Mudimela NanoMaterials Group TKK

Research Substrate CVDConcrete/Cement

a. SIngle wall CNT at 590 °C b. Double wall CNT at 900 °C c. Triple wall CNT at 970 °C d. Quadruple wall CNT 1070 °C a b d CO as carbon source, H 2 for reduction Submitted to JPC C POSTER c

A Novel Cement-based Material

Cement/Concrete  The main features of the CNTs which attracted the most attention are high tensile strength and elastic modulus, high electrical and thermal conductivity.  Adding CNTs will reduce crack formation in reinforcing concrete  Two main problems associated with the incorporation of CNTs into any kind of matrix: uniform dispersion within the matrix and sufficient bonding.  Growing nanotubes/nanofibers on cement improve the bonding and dispersion

Ceramic boat with cement Few grams per day! Bulk productions it is not suitable Temperature 550 °C-750 °C. 5 min reduction (H 2 ) 20 min growth (C 2 H 2 ). Initially Ar was passed inside the reactor. Reduction period: H 2 (280 sccm) = 5 min, Growth period: C 2 H 2 (28 sccm), H 2 (280 sccm) = 20 min

Screw feeder reactor Oxides Cement type CaOSiO 2 SO 3 Fe 2 O 3 Al 2 O 3 MgOK2OK2ONa 2 O SR cement

a b c d a.C 2 H 2 b.C 2 H 2 CO 2 c.CO C 2 H 2 d.C 2 H 2 CO CO 2

TEM images: C 2 H 2 CO 2 C2H2C2H2

T[oC]T[oC] C 2 H 2 [cm 3 min -1 ] CO 2 [cm 3 min -1 ] CO [cm 3 min -1 ] Y cem [%] Y Fe [%] Effect of experimental conditions of the product yield obtained on the basis of TGA data and calculated per mass of cement (Y cem ) or iron (Y Fe ).

XRD spectra of (1) pristine SR cement and CHM produced (2) at 500 °C in C 2 H 2 + CO 2 ( cm 3 min -1 ), (3) at 575 °C under C 2 H 2 + CO 2 ( cm 3 min -1 ) reveal the gypsum (G) decomposition under thermal treatment and appearance of the graphite (C). In order to investigate the produced hybrid structures in the quality of a building component, we prepared cement pastes on the basis of the CHM and tested their compressive and flexural strengths and electrical resistance. For the current tests we used beams with dimensions of 60x10x10 mm 3 prepared using Teflon molds and cured in water at 20 ºC for 7, 14 and 28 days.

Fraction of CHM [%] Synthesis conditionsCompressive strength [MPa] Electrical resistivity [M . cm] Temp [ºC] Gas flow rate, [cm 3 min -1 ] C2H2C2H2 CO 2 CO Mechanical (after 28 days curing in water) and electrical (1 day after mechanical testing) properties of cement paste prepared by adding different samples of SR CHM.

The results of SEM/EDX investigations of the hardened cement paste (curing in water for 28 days) after the mechanical test. The images reveal the presence of carbon nanomaterials (indicated by arrows) and cement composition elements: O, Al, Si and Ca.

bca Fig: (a) SEM image of CNFs at 550 °C (b) & (c) TEM images at 550 °C and 750 °C Nanotube Growth on Silica

Clinker with CNFs at 750 °C (using 250 ccm CH 4, 250 ccm H 2 )

Cement and Concrete Research Journal (submitted) Applied Physics Letters (Submitted ???????) Letters to carbon (In preparation) CONCLUSIONS:  First time cement particles were utilized as a support and as a catalyst, which allowed us to synthesize novel hybrid nanostructured material, wherein CNTs and CNFs attached to cement particles provided a very good dispersion of the carbon nanomaterials in the cement matrix.  This hybrid material was synthesized by a simple one step CVD method, which can be easily combined into industrial cement production without significant increase in the cement cost.

ACKNOWLEDGEMENTS Albert Nasibulin, Larisa Nasibulin, Esko Kauppinen Andrzej Cwirzen, Karin Habermehl-Cwirzen, Vesa Penttala, Maarit J. Karppinen NanoMaterials Group, TKK Laboratory of Inorganic Chemistry, TKK Laboratory of Building Materials Technology, TKK VTT, Espoo Unto Tapper Thanks to NGS - NANO

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