Experimental Study on Carbonation Durability of Kaolin Strengthened with Slag Portland Cement

Abstract

Slag Portland cement is an environmentally friendly and energy-saving product, which is widely used in cement-reinforced soil. This study used slag Portland cement-reinforced soil as the research object and P.O 42.5 + kaolin (POK) as the reference group. The carbonation depth and strength of P.S.A 42.5 + kaolin (PSK) at different curing times were analyzed using carbonation depth, uniaxial ground pressure strength, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The test results show the following: (1) The active substances in PSK samples can react with calcium hydroxide produced during cement hydration and can reduce the content of OH−. The PSK samples react with OH− and CO2 in the carbonation environment. Both processes considerably reduce the content of OH−. (2) Due to the decrease in OH− content, the carbonation durability of slag Portland cement-reinforced soil is significantly less than that of ordinary Portland cement. (3) The carbonation of slag Portland cement-reinforced soil improves its strength. (4) The results of SEM + EDS and XRD confirm the carbonation depth and strength of the POK and PSK samples. The results show that PSK has important applications in subgrade or building grouting materials and in cement-soil mixing piles (walls).

Concreto de cimento Portland dopado com quitosana: propriedades mecânicas e microestrutural

“…Picos de carbonato de cálcio ocorreram em 2θ = 29,1° e 47, 1°. A presença da fase carbonato de cálcio pode ser devido à carbonização durante o experimento pelo CO 2 atmosférico e hidróxido de cálcio [81,82]. Além disso, LIANG et al [83] relata que a concentração de quitosana tem forte influência nas morfologias do CaCO 3 .…”

Associated Effects of Sodium Chloride and Dihydrate Gypsum on the Mechanical Performance and Hydration Properties of Slag-Based Geopolymer

“…However, excessive amounts of gypsum can lead to the production of excessive amounts of AFt [59], resulting in volume expansion and the breaking of hardened paste. Previous studies have shown that the optimal proportion of gypsum in slag-based geopolymer is between 6% and 10% [60]. Additionally, the reactivity of slag powder increases significantly when the concentration of gypsum and quicklime is within the range of 5-10% and 10-20%, respectively [61].…”