Behavioral study on cement mortar and cement concrete admixed with multi walled carbon nanotubes

Abstract

i newlineABSTRACT newlineConventional cementitious composites greatly underutilize the potential of cement. newlineBy careful selection of the amount of free water, additives, admixtures and newlineaggregates, it is possible to achieve higher compressive strength at very little newlineadditional material cost. But corresponding improvement in flexural strength could newlinenot simultaneously be achieved. Research already carried out has established that newlineaddition of fibres improve the static flexural strength, fatigue, ductility and fracture newlinetoughness. However, addition of fibres has no beneficial effect on compressive newlinestrength as they have only crack-bridging property but do not have pore filling effect. newlineIn this connection, addition of nano fibres such as carbon nano tubes (CNTs), being newlinefiner and fibrous, has the potential to fulfil both the above objectives. In the present newlineinvestigation, an extensive review was carried out on various available literatures on newlineadmixing CNTs in cementitious composites. The following aspects were identified as newlinethe research gaps where more investigations are required. newlinei. Effect of density of multi-walled CNTs (MWCNTs) on cement mortar and newlineconcrete, by admixing MWCNTs in percentage by weight of cement newline(represented as wp) newlineii. Pressure sensitive, transport and durability properties of cement mortar beyond newline2 wp newlineiii. Pressure sensitive, transport and durability properties of cement concrete newlineadmixed with multi-walled CNTs newlineiv. pH value of cement mortar and concrete integrally dispersed with multiwalled newlineCNTs newlinev. Electrochemical properties of concrete admixed with multi-walled CNTs - newlinecement ratios beyond 1 wp. newlineIn the present investigation, some of the aspects were proposed to be investigated. newlineThree different types of multi-walled CNTs viz. Type-A, Type-B and Type-C with newlinedensity ranges of 0.15 - 0.35 g/ cm3, 0.20 - 0.35 g/ cm3 and 0.04 0.06 g/ cm3, newlinerespectively were used in this research work. These multiwalled CNTs were pristine newlineii newlineand surface untreated. No surfactants were used during the preparation of specimens. newlineThe present investigation was divided into five modules. newlineExperimental works were carried out with cement mortar specimens under modules 1 newlineto 4 and with cement concrete specimens under module-5. Finally, a cost analysis has newlinealso been carried out. The results and outputs of the present research work have a newlinenovel contribution at macro-level and a high potential application in the construction newlinefield with a greater scope for further research works with various other combinations. newlineKeywords: mortar; concrete; multi-walled carbon nanotubes; composites; matrix newline