Synthesis and microstructure analysis of autoclaved aerated concrete with carbide slag addition

Abstract

Synthesis of autoclaved aerated concrete (AAC) has been carried out with carbide slag addition, and the carbide slag could be used as a main material to produce the AAC with the compressive strength about 2 MPa and the density below 0.6 g•cm 3 . In this study, quartz sand acted as frame structure phase in the matrix, and quartz addition also infl uenced the Si/Ca of starting material. Tobermorite and CSH gel were formed readily at 62%, which seemed to enhance the compressive strength of samples. Curing time seemed to affect the morphology of phase produced, and specimen with the plate-like tobermorite formed at 10 h appeared to have a better compressive strength development than the fi ber-like one at 18 h. The higher curing temperature seemed to favor the tobermorite and CSH gel formation, which also exerted a signifi cant effect on the strength development of the samples. On the micro-scale, the formed CSH gel was fi lled in the interface of the matrix, and the tobermorite appeared to grow in internal-surface of the pores and interstices. The tobermorite or/and CSH formation seemed to densify the matrix, and therefore enhanced the strength of the samples.

Thermal and hydrothermal treatment of UHPC: influence of the process parameters on the phase composition of ultra-high performance concrete

“…Under equilibrium conditions tobermorite decomposes to xonotlite and quartz, which significantly decreases the compressive strength of the building material [47]. This undesired xonotlite formation during AAC production is attributed to unfavourable selection of the raw materials as well as to excessively high autoclaving temperatures or autoclaving times [47][48][49][50].…”

Influence of Recipe Factors on the Structure and Properties of Non-Autoclaved Aerated Concrete of Increased Strength

“…In particular, not only the technological process of obtaining aerated concrete is complex, but also the technological line itself, which often consists of more expensive equipment. In this regard, the most high-quality, but at the same time the most expensive, type of cellular concrete is the so-called gas silicate or autoclaved aerated concrete [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

Mathematical Modeling and Experimental Substantiation of the Gas Release Process in the Production of Non-Autoclaved Aerated Concrete

“…In terms of cost characteristics, non-autoclaved cellular concretes significantly outperform autoclaved competitors due to the significantly reduced cost of production and manufacture of such concretes and less environmental impact. From the point of view of technological and recipe factors, there are quite a lot of studies of non-autoclaved and autoclaved aerated concrete [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. However, from the point of view of fundamental science, some gaps should be filled with additional research in the phenomenon of outgassing during the formation of the structure of non-autoclaved aerated concrete.…”

“…Studies of the influence of various fibers and microsilica on lightweight concrete’s mechanical properties (compressive and bending strength) are also of great importance [ 11 , 12 , 13 , 14 , 15 , 16 ]. For example, in [ 11 ], the change in the value of thermal conductivity, compressive strength, and bending of autoclaved aerated concrete was studied when polypropylene, carbon, basalt, and glass fibers were added to autoclaved aerated concrete.…”