Influence of CO2 concentration on the performance of MgO cement mixes

Enhancing the performance of MgO-activated slag-fly ash mixes by accelerated carbonation

“…Once the 28 days of curing were completed, both set of samples were subjected to accelerated carbonation under an elevated CO2 concentration to increase the rate of the carbonation reaction. In line with the findings of previous studies [33,37], 10% CO2 was determined as an ideal concentration for the microstructural and mechanical development of the prepared samples, which were cured under 10% CO2, 30±1°C and 80±2% RH. Following the results presented in earlier studies [30], the carbonation duration was extended up to 70 days (i.e.…”

“…Further improvements in the performance of the developed RM activated-GGBS-FA samples were achieved via the conversion of the unhydrated MgO into hydrated magnesium carbonates (HMCs) such as rosette-like hydromagnesite (4MgCO3•Mg(OH)2•4H2O), needlelike nesquehonite (MgCO3•3H2O), and acicular artinite (MgCO3•Mg(OH)2•3H2O) [31,32]. This was enabled by subjecting the samples to elevated concentrations of CO2 during curing [33,34]. The utilization of high concentrations of CO2 in the carbonation process not only led to a reduction in porosity and provided a binding network facilitated by the formation of HMCs, thereby improving sample performance [21,30,31,35,36], but also shed light on the feasibility of reducing CO2 emissions asscociated with cement production.…”

Mechanical and microstructural changes in reactive magnesium oxide cement-based concrete mixes subjected to high temperatures

“…It is noted that due to diffusion control arising from the matrix densification, the carbonation level was postulated to be non-uniform throughout the sample depth. This was proven in a previous study with X-ray computed tomography based on a correlation between grayscale and sample density [27,70]. Quantification of the sequestered CO2 with TGA also confirmed the uneven carbonation where more extensive carbonation was observed for the exterior regions of RMC samples even after prolonged CO2 exposure [26].…”

“…Lorentz distribution was chosen with manually selected initial peak locations. Iterations were subsequently performed to achieve a respective coefficient of determination R 2 greater than 0.99. prevented the progress of the carbonation reaction and reduced the rate of strength gain [26,70]. As a result, C20 samples exhibited a marginal strength gain to 58 MPa at 14 days and 60…”

Advances in the hydration of reactive MgO cement blends incorporating different magnesium carbonates

“…Despite enhancing the hydration reaction, the inclusion of MA or M in RMC formulations did not change the composition of the hydration products. Alternatively, the use of H influenced the [45]. Furthermore, the artinite peak at 32.8°2h was more obvious in sample 20H.MA than it was in sample 20H.…”