LHOKNGA, Indonesia - An army of workers rebuilds a cement plant once strewn with bodies. A four-lane highway slowly takes shape along a coast shattered by giant waves. Roof tiles on new houses and schools glint in the tropical sun.

After the tsunami struck three years ago today, taking 230,000 lives in 12 Indian Ocean countries from East Africa to Indonesia, the world pledged about $13.6 billion to house and feed survivors and rebuild devastated coasts.

Now the assistance is drying up, and the recipients are facing the challenge of standing up unaided.

Results of three years of reconstruction are visible along the coast of Indonesia's Aceh province, the region hit hardest by the Dec. 26, 2004, disaster. Some of those involved are calling it a model of post-disaster reconstruction.

"The developments on the ground are very pleasing," said Kuntoro Mangkusubroto, head of the government reconstruction agency. "I would say we are around 80 percent complete."

Some fear a hard landing when major reconstruction work ends around mid-2008.

The aid that has built roads, schools, and more than 100,000 homes has also powered local economies. Aid agencies hired thousands of construction workers, rented homes and offices, employed drivers and translators, and patronized restaurants and hotels.

The huge injection of money boosted the largely agriculture-based economy in Aceh, home to 4.2 million people. Cars and motorcycles jam the provincial capital of Banda Aceh. Hotels, cafes and shops seem to be going up on every corner.

"This is dangerous; it is like a bubble," said Zainul Arifin, the head of Aceh's investment board. Like many, he earned thousands of U.S. dollars renting his house to a Western aid agency. "When the United Nations and the aid groups leave, we have to be ready with new livelihoods."

None of that diminishes the progress to date.

More than $2 billion has been spent in Thailand to rebuild the southern coast, where resorts were badly damaged and 8,000 people died. Almost all the work is complete, said Bundit Theveethivarak, director of disaster mitigation at the Interior Ministry.

In Sri Lanka, the second-hardest-hit country, "the picture is pretty good," said David Evans, a U.N. official there. Some reconstruction has been hampered by fighting between the government and the Tamil Tigers rebel group.

Indonesia has experienced an added benefit: The tsunami jolted the government and a rebel movement in Aceh into signing a peace deal after decades of war that killed 15,000.

By April 2009, when the reconstruction agency's mandate officially ends, Indonesia expects to have spent $8 billion in Aceh, $1.9 billion more than the estimated cost of repairs. The extra money will let the province "build back better," according to the reconstruction agency.

For example, the four-lane highway, funded mainly by the U.S. government, is replacing a two-lane coastal road that in some places was completely washed away. In central Banda Aceh, workers are laying wide sidewalks, something rarely seen in Indonesia.

With so much money sloshing around, some was wasted. About 20 percent of the new homes in some areas are empty. People who did not need homes gladly accepted them when they were offered free. Complaints of poor quality abound, and some homes still lack plumbing and electricity.

Aid agencies and the government say that with hundreds of thousands left homeless after the tsunami, they were under intense pressure to build as many homes as they could and to do so quickly.

Mangkusubroto said that next year would be "about filling in the gaps" in housing.

Kickbacks and bid-rigging have occurred, but the widespread corruption many feared was held in check by strict auditing, officials and aid workers said.

With aid agencies winding down operations or already gone, attention is shifting to attracting private investment to create jobs.

So far only one major foreign company, France-based Lafarge SA, is making a significant investment, spending $90 million to rebuild the seaside cement factory in Lhoknga, just outside Banda Aceh.

About 200 local workers, supervised by Chinese engineers, are pulling out what cannot be fixed and rebuilding the rest. The facility is also getting a new 32-megawatt power plant.

An Irish firm announced a plan last year to turn the island of Sabang off northern Aceh into a shipping hub, but squabbling among local politicians has delayed the project, according to Sabang officials.

The island sits at the entrance to the Malacca Strait, a strategic waterway through which many container ships pass. The plan envisions ships unloading their wares onto smaller boats at Sabang for regional distribution, a role Singapore plays today.

The concerns for potential investors mirror those throughout Indonesia: an absence of clear laws, creaky infrastructure, uncertainty over landownership, copious red tape.

"Investors are sniffing around, which is a good sign," said David Lawrence, head of a World Bank agency tasked with helping the province attract investment, "but there's some way to go yet."