The heat from the flames evaporated components of the asphalt, causing it to crack and crumble.
Emergency officials closed the interstate to all traffic between the Pocatalico exit and the I-77/79 split in Charleston following the explosion. Kanawha County Route 21 between Pocatalico and Charleston was also limited to emergency vehicles only.
Paving crews had to mill interstate lanes down to the original concrete, removing between 4 to 5 inches of scorched asphalt, before laying down new asphalt on the road.
Crews finished laying asphalt on the northbound lanes around midnight.
Work had to stop briefly around 1 a.m. while workers with NiSource-owned Columbia Gas Transmission conducted a pressure test on gas lines around the explosion area.
The American Red Cross and workers from the Gino's Pizza location in Sissonville brought paving crews with food and coffee as they continued working overnight.
Paving crews had about 200 tons of asphalt left to put down on the southbound lanes, as of 7 a.m. Wednesday.
Finishing the work means drivers will be able to avoid lengthy detours around the area.
Before the repairs were complete, state officials had asked northbound interstate traffic to detour to I-79 north to Clarksburg/Bridgeport and take U.S. 50 west to reach I-77 at Parkersburg.Southbound traffic was asked to exit I-77 at Ripley and take W.Va. 62 west to Point Pleasant. There, drivers were told to take U.S. 35 south to Interstate 64 near Winfield and travel east to reconnect with I-77 in Charleston.