Friends identified the soldier as Jesse Reed, a native of Whitehall Township, Lehigh County, who most recently lived with his wife and nine-month-old son in Fayetteville, North Carolina.
His wife, Heather, a native of Northampton, Northampton County, is pregnant with the couple's second son.
Friends said Reed, on his latest deployment since late December, was expected to return home next month for the baby's birth.
Reed was a 2002 graduate of Whitehall High School and a 2008 graduate of Lehigh Carbon Community College, according to his Facebook page.
He's been enlisted with the Army as a heavy construction equipment operator since November 2008.
A friend of Reed's, identified as Adam Keys, also of Whitehall Township, reportedly suffered serious injuries in the attack.
The Department of Defense has not yet formally identified the victims.
A statement from the NATO-led international force said four troops were killed by the roadside bomb while a fifth died the same day of wounds from a gun battle.
The deaths make eight Americans killed within 24 hours in the volatile south of the country, where U.S. troops are making a push to secure Taliban-dominated areas.
Three other Americans died late Tuesday in a Taliban attack on a police headquarters in Kandahar, the largest southern city.
