Influence of quartz particle size on the chemical and mechanical properties of autoclaved aerated concrete (II) fracture toughness, strength and micropore

Hydrothermal Solidification of Kaolinite–Quartz–Lime Mixtures

“…For the specimens with Al/(Si ϩ Al) ϭ 0 to 0.24, these peaks, which correspond to the interparticle spaces, shift toward finer diameters up to ϳ0.01 m with increasing treatment time. For specimens with Al/(Si ϩ Al) ϭ 0, however, the pore diameter peak at ϳ0.01 m, observed after 2 h of treatment, shifts toward coarser diameters for treatment times of Ն5 h. This pore coarsening phenomenon is due to the formation of gyrolite, as has been reported by Isu et al, 18 and appears to be a reason for the observed strength reduction. The reason for the observed strength development in the specimens with Al/(Si ϩ Al) ϭ 0 and 0.05 is the formation of fine pores 0.01 m in size accompanying the precipitation of C-S-H and tobermorite.…”

“…This trend was particularly clear for Al/(Si ϩ Al) ϭ 0 and was thought to be caused by the formation of gyrolite. 17,18 In the case of the kaolinite-rich specimens with Al/(Si ϩ Al) ϭ 0.24 to 0.50, flexural strength was 15 to 20 MPa after 2 h treatment and tended to increase very slightly for longer treatment times.…”

“…The decrease in strength observed after long periods of hydrothermal treatment appeared to be related to the formation of these gyrolite crystals. 17,18 For Al/(Si ϩ Al) ϭ 0.45 and 0.50, only plate-shaped kaolinite particles were observed. The presence of hydrogarnet cubes 1 to 2 m in size was observed previously in the case of hydrothermally treated specimens made with slag as the starting material.…”

Influence of zeolite additive on properties of autoclaved aerated concrete

“…Gyrolite (Ca 4 (Si 6 O 15 )(OH) 2 Á 3H 2 O) was formed with an increased autoclaving time in case when finer quartz was used. Isu et al [7] showed that the formation of gyrolite after reaction time of 64 h using finer quartz decreased the compressive strength and the Young's modulus due to changes in the micro-pore size distribution.…”

Effect of fineness and dosage of aluminium powder on the properties of moist-cured aerated concrete

“…The compressive strength is reported to be influenced by the shape, size and method of pore formation, age of the sample, direction of loading, characteristics of ingredients used and method of curing [15]. Earlier studies considered the influence of dosages of aluminium powder by keeping the fineness of aluminium powder constant [16].…”