Microstructure of Autoclaved Aerated Concrete Hydration Products in Different Water-to-Binder Ratio and Different Autoclaved System

Abstract:

Using XRD and SEM analysis, the types and morphology of autoclaved aerated concrete (AAC) hydration products in different water-to-binder ratio (w/b) and different autoclaved system were studied. Strength test shows that, Using w/b=0.25 and autoclaved curing 190°C for 8h, AAC with dry density 765kg/m3 and compressive strength 7.5MPa was made. XRD and SEM analysis indicate that, the higher the autoclaved temperature is, the smaller the size of hydration products (most of them are tobermorite and hydrogamet) is, and the crystallinity has a little increase; with the extension of autoclaved time, the size of products is smaller, the crystallinity is first increased and then decreased, the crystal form of tobermorite turns 1.1nm into 1.4nm; the less the w/b is, the smaller the size of products is, and the higher the crystallinity is, and tobermorite turns 1.1nm into 1.4nm.

• Periodical: Advanced Materials Research (Volumes 602-604)
• Pages: 1004-1009
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.602-604.1004
• Online since: December 2012
• Authors: Zhao Ming Huang, Yu Fei Yuan, Ze Jie Chen, Zi Yun Wen
• Keywords: Autoclaved Aerated Concrete (AAC), Autoclaved System, Hydration Product, Water-to-Binder Ratio

References

[1] N. Narayanan, K. Ramamurthy. Microstructural investigations on aerated concrete [J]. Cement Concrete Research, 2000(30): 457-464

DOI: 10.1016/s0008-8846(00)00199-x

[2] N. Narayanan, K. Ramamurthy. Structure and properties of aerated concrete: a review [J]. Cement and Concrete Composites, 2000, 22:321-329

DOI: 10.1016/s0958-9465(00)00016-0

[3] Sun Baozhen, Jia Chaunjiu. The mathematical relationship of aerated concrete between pore structure and strength [J]. Silicate Building Products,1983(05): 25-27(in Chinese)

[4] N. Narayanan, K. Ramamurthy. Structure and properties of aerated concrete: a review [J]. Cement and Concrete Composites, 2000, 22:321-329

DOI: 10.1016/s0958-9465(00)00016-0

[5] Tam CT, Lim TY, Lee SL. Relationship between strength and volumetric composition of moist-cured cellular concrete. Mag Concr Res1987; 39:12-8.

DOI: 10.1680/macr.1987.39.138.12

[6] ASTM C 618 Standard specification for fly ash and raw or calcined natural pozzolan for use as a mineral admixture in Portland cement concrete, American Society for Testing and Materials, Philadelphia, (1972)

DOI: 10.1520/c0618-15