3.1. Carbonation depth
Figs. 1–3 show the results of carbonation depth of G30, G40 and
G50 with different CO2 concentration levels at different test ages,
respectively. Based on CO2 concentrations used in this study, four
CO2 concentration change zones can be identified (see Fig. 1); they
are zone r for 2–10% CO2, zone s for 10–20% CO2, zone t for 20–
50% CO2, and zone u for 50–100% CO2.
From Fig. 1, it can be observed that the concrete carbonation
depth increased with increased CO2 concentration but the significance
is reduced when the CO2 concentration is higher than 20%.
The increase rates in different zones are also different. In Fig. 1,
the arrow lines display the slopes of 56d carbonation depth lines
for different CO2 concentration zones. The slope of zone r (2–
10%) is the biggest. It indicates that when CO2 concentration
increased from 2% to 10%, increase of concrete carbonation depth
is the most obvious. The slope of zone s (2–10%) is smaller than
that of zone r. The slope of zone t reduces greatly, and the slope
3.1. Carbonation depthFigs. 1–3 show the results of carbonation depth of G30, G40 andG50 with different CO2 concentration levels at different test ages,respectively. Based on CO2 concentrations used in this study, fourCO2 concentration change zones can be identified (see Fig. 1); theyare zone r for 2–10% CO2, zone s for 10–20% CO2, zone t for 20–50% CO2, and zone u for 50–100% CO2.From Fig. 1, it can be observed that the concrete carbonationdepth increased with increased CO2 concentration but the significanceis reduced when the CO2 concentration is higher than 20%.The increase rates in different zones are also different. In Fig. 1,the arrow lines display the slopes of 56d carbonation depth linesfor different CO2 concentration zones. The slope of zone r (2–10%) is the biggest. It indicates that when CO2 concentrationincreased from 2% to 10%, increase of concrete carbonation depthis the most obvious. The slope of zone s (2–10%) is smaller thanthat of zone r. The slope of zone t reduces greatly, and the slope
การแปล กรุณารอสักครู่..