Table 4.
Air concentrations of asphalt vapor (p.p.m.) collected by personal air sampling among screedmen.
| N a | GMb | GSDc | Min–max | P-value | GSD for the difference between HMA and WMA | |
|---|---|---|---|---|---|---|
| WMA | 15 | 0.06 | 2.63 | 0.007–0.248 | ||
| HMA | 15 | 0.07 | 3.02 | 0.008–0.277 | 0.63 | 3.59 |
| Additive WMA | 9 | 0.10 | 1.99 | 0.023–0.248 | ||
| HMAd | 9 | 0.10 | 2.77 | 0.011–0.277 | 1.00 | 4.05 |
| Foam WMA | 6 | 0.03 | 2.37 | 0.007–0.076 | ||
| HMAe | 6 | 0.04 | 3.05 | 0.007–0.134 | 0.44 | 3.18 |
The results of all measurements during paving with warm mix asphalt (WMA) and hot mix asphalt (HMA) are shown as well as results stratified based on the use of additive or foam WMA. The statistical significance of the observed differences in geometric mean (GM) was tested by performing a paired t-test on ln-transformed data.
aNumber of measurements.
bGeometric mean.
cGeometric standard deviation.
dCorresponding road sections with additive WMA.
eCorresponding road sections with foam WMA.