JOURNAL OF MATERIALS IN CIVIL ENGINEERING, cilt.25, sa.2, ss.266-273, 2013 (SCI-Expanded)
For construction of roads and highways, a large amount of aggregate usage is needed. Because the natural aggregate resources are
limited, the demand for the use of alternative aggregates has increased. For this reason, borogypsum in Turkey was used as a mineral filler
aggregate in hot-mix asphalt concrete. When this is directly released to nature as boron waste, it may cause various environmental problems.
In order to prevent this waste’s harmful effects to the environment, the use of borogypsum as an alternative aggregate in highway engineering
may be effective. For this purpose, the physical properties of borogypsum were investigated by thermogravimetry differential thermal analysis
(TG-DTA), x-ray diffraction (XRD), and scanning electron microscope energy dispersion analysis of x-ray (SEM-EDAX). Also, the surface
properties of borogypsum were identified by polarized optical microscope (POM). In this study, two groups of hot-mix asphalt concrete were
obtained. For the first group, asphalt concrete was produced with limestone aggregate, and for the second one, borogypsum was used as
mineral filler in asphalt concrete. In both groups, limestone was used as fine and coarse aggregate. Marshall stability and other mechanical
properties were determined. It is believed that the evaluated borogypsum has a similar crystal structure with tincalconite and its usage for hotmix
climate regions may be effective to reduce problems. Also, another crucial finding is that using borogypsum as a mineral filler aggregate
in asphalt concrete can be convenient for the binder course of pavements exposed to heavy traffic potential.