Hydration, mechanical properties and microstructure of Portland cement substituted by a combination of metakaolin and nano-clay

2^nd International Conference and Exhibition on Materials Science & Engineering

October 07-09, 2013 Hampton Inn Tropicana, Las Vegas, NV, USA

Jianqiang Wei and Christian Meyer

Accepted Abstracts: J Material Sci

Abstract :

Using natural fibers like sisal fiber in fiber reinforced cement composites is being considered because of the various benefits in regard to sustainable development. However, such organic materials are subject to degradation caused by reacting with the alkaline pore solution. A possible remedy is the combined substitution of metakaoline (MK) and nanoclay for Portland cement (PC). This paper reports on a study of such substitution through mechanical properties, microstructure and the hydration products at different ages. The mechanical properties were studied using the compressive strength development of cement mortar. The characteristics of hydration products were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetry analysis (TGA). Our results show that the combination of metakaolin and Nano clay can improve the hydration of cement more effectively with better microstructure and mechanical properties than mixes without them. The calcium hydroxide (CH) and ettringite in cement hydration products were removed effectively due to the substitution of MK and nanoclay, which improved both Al/Ca and Si/Ca ratios of cement hydration products due to the high content of SiO 2 and Al 2 O 3 .

Biography :

Jianqiang Wei is a Ph.D. candidate advised by Professor Christian Meyer and co-advised by Professor Shiho Kawashima in Department of Civil Engineering and Engineering Mechanics at Columbia University in the City of New York. His research is on fiber & microfiber reinforced cement composites, sustainable composite materials, with an emphasis on application and degradation of natural resource in sustainable construction materials, hydration of cement, and advanced nano-modification of cement based material. He is also interested in carbon fibrous reinforced cement, durability of concrete, as well as the improvement of infrastructural materials in micro- or nanoscale.