The influence of cellulose nanocrystal additions on the performance of cement paste |
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| Affiliation: | 1. School of Materials Science and Engineering, Purdue University, West Lafayette, IN 47907, USA;2. School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA;3. Forest Products Laboratory, US Forest Service, Madison, WI 53726, USA;1. Department of Cellulose and Paper Technology, Faculty of New Technologies Engineering, Shahid Beheshti University, Science and Research Campus, Zirab, Savadkooh, Mazandaran, Iran;2. Department of Wood and Paper Science and Technology, Faculty of Natural Resources, University of Tehran, Karaj, Iran;3. Department of Civil Engineering, Architecture and Building, Faculty of Engineering & Computing, Sir John Laing Building, Coventry University, Coventry, UK;4. Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran;1. Department of Biosystems Engineering – Faculty of Animal Science and Food Engineering, University of Sao Paulo, Duque de Caxias Norte Street, 225, 13630-000 Pirassununga, SP, Brazil;2. Department of Materials and Technology – Faculty of Engineering, Sao Paulo State University, Ariberto Pereira da Cunha, 333, 12516-410 Guaratinguetá, SP, Brazil;1. Cement and Concrete Research Group, Department of Civil Engineering, Université de Sherbrooke, 2500, Boulevard de l’Université, Sherbrooke, QC, J1K 2R1, Canada;2. Vanier Scholar of the Natural Sciences and Engineering Research Council of Canada, Canada;1. School of Engineering, Universidad Pontificia Bolivariana, Medellín, Colombia;2. Universidad de Buenos Aires, Facultad de Ingeniería, Buenos Aires, Argentina;3. Instituto de Tecnología de Polímeros y Nanotecnología (ITPN), Universidad de Buenos Aires/CONICET, Buenos Aires, Argentina;1. Department of Civil Engineering, University of Toronto, 35 St. George Street, Toronto, ON M5S 1A4, Canada;2. Centre for Biocomposites and Biomaterials Processing, Faculty of Forestry, University of Toronto, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada |
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| Abstract: | The influence of cellulose nanocrystals (CNCs) addition on the performance of cement paste was investigated. Our mechanical tests show an increase in the flexural strength of approximately 30% with only 0.2% volume of CNCs with respect to cement. Isothermal calorimetry (IC) and thermogravimetric analysis (TGA) show that the degree of hydration (DOH) of the cement paste is increased when CNCs are used. The first mechanism that may explain the increased hydration is the steric stabilization, which is the same mechanism by which many water reducing agents (WRAs) disperse the cement particles. Rheological, heat flow rate measurements, and microscopic imaging support this mechanism. A second mechanism also appears to support the increased hydration. The second mechanism that is proposed is referred to as short circuit diffusion. Short circuit diffusion appears to increase cement hydration by increasing the transport of water from outside the hydration product shell (i.e., through the high density CSH) on a cement grain to the unhydrated cement cores. The DOH and flexural strength were measured for cement paste with WRA and CNC to evaluate this hypothesis. Our results indicate that short circuit diffusion is more dominant than steric stabilization. |
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| Keywords: | Cellulose nanocrystal CNC Degree of hydration Ball-on-three-ball flexural test Steric stabilization Short-circuit diffusion |
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