Capillary Absorption and Oxygen Permeability of Concrete Reinforced with Carbon Nanotubes

Abstract

This article focuses on the transport properties of concretes reinforced with different amounts (0.05–0.5 wt.%) of pristine and functionalized carbon nanotubes (CNTs) with distinct aspect ratios (300, 667). To this end, concretes with different water-to-cement ratios were tested at distinct ages in terms of capillary absorption and oxygen permeability. The results show the ability of CNTs to decrease both capillary water absorption and oxygen permeability up to 42 and 71 %, respectively, depending on the type and amount of CNTs. Compressive strength increased up to 21 %. The best performance was found for 0.1 % CNTs of a lower aspect ratio. Higher amounts of CNTs did not lead to a proportional reduction of transport properties. CNTs were more effective in dried concrete compared to saturated ones where they could better participate in the pore refinement and microcrack retention. Transport properties correlated well with compressive strength, but oxygen permeability was greater affected by the incorporation of CNTs than other tested properties.

Influence of Cracking on the Durability of Reinforced Concrete with Carbon Nanotubes

“…As expected, the incorporation of CNT enabled the reduction of both coefficients of absorption, indicating the refinement of the concrete microstructure. However, contrary to what was found in a previous study [16], the highest reduction, of around 27%, was obtained for Cabs,6-72h. In fact, a greater contribution of CNT at early age would be expected, involving the water absorption of drier and more cracked surface concrete [30].…”

“…During the last decade, carbon nanotubes (CNT) have been studied as a reinforcement material for cement-based composites [16][17][18][19][20][21][22][23][24][25][26]. The growing interest in this field comes from the desire to modify the cement matrix at the scale of their main compounds, by taking advantage of the outstanding properties of CNT.…”

“…Regarding the characterization of CNT-reinforced cementitious materials, various studies have been carried out focusing on the physical, mechanical and durability characterizations of cement pastes and mortars [20,22,23,30], and few on those properties of CNT-reinforced concrete [16][17][18]21,24]. The studied properties of CNT-reinforced cementitious materials include compressive strength [16][17][18][19][20][21][22][23][24], flexural strength [17,19,20,23,24], splitting tensile strength [17], modulus of elasticity [17,18,22,23], ultrasonic pulse velocity [18,23], fracture toughness [17,23], steel-concrete bond [21], shrinkage [18,22,23], creep [18], microscopic analysis [17][18][19][20][22][23][24], capillary absorption [16,22,…”

Concreto de baja permeabilidad para pilotes prefabricados de muelles construidos en zonas de salpicaduras y mareas utilizando nanotubos de carbono de pared múltiple

“…Este comportamiento, según lo indicado en la Ref. [40], está relacionado con el efecto positivo del NTC sobre la hidratación del cemento a edades tempranas.…”

“…Los resultados expuestos, presentan una igual tendencia de aumento de resistencia que los mostrados en el presente trabajo. Este comportamiento, según lo indicado por [45], se atribuye a la reactividad química del NTC con la matriz que produce un nanocompuesto mejorado en sus propiedades mecánicas de resistencia.…”