The art world has lost one of its most loved and respected and ebulliently rebellious figures. Robert Rauschenberg, the American pop artist, died of heart failure on Monday at his home in Florida. He was 82.

Rauschenberg was famous the world over for his assemblages: collage-style pieces built up from the sort of junk that most people would dump out on the street. His “combine” pieces included items as varied as stuffed goats, old tyres, tennis balls and traffic barricades.

From the vantage point of half a century later it is easy to forget quite how radical this idea once seemed.

Rauschenberg was a pioneer in the big, bold American sense of the world. He was a true revolutionary. Doing exactly the reverse of what his first teacher, Josef Albers, taught him at the renowned Black Mountain school, he picked up the project that Marcel Duchamp had first mooted with his ready-mades and headed off with it into new territories.

He was a man with a mission. And his aim, as he once said, was to occupy the gap that had opened up between art and life. Nothing was untouchable as far as he was concerned. “I really feel sorry for people who think things like soap dishes or mirrors or Coke bottles are ugly,” he once said, “because they're surrounded by things like that all day long and it must make them miserable.”

Misery was not something that this garrulous, whisky-drinking, unstoppably cheerful provocateur suffered from. Driven by a protean spirit of experimentation and a passion for discovery, he began his career by leaving Abstract Expressionism ostentatiously behind him, persuading Willem de Kooning, among its most celebrated exponents, to give him a drawing so that he could erase it and create a new work.

Rauschenberg was irrepressibly prolific. He didn't care about consistency. His appetites were omnivorous; he devoured ideas in the way that modern-day Americans knock back Big Macs.

The artist, who began by painting completely white canvases, moved on to make all-black works before developing his collages. “The artist's job is to be a witness to his times,” he said.

He moved on with history, experimenting, for example, with incorporating up-to-the-minute photographed images from the 1960s in his pieces, most memorably with pictures of John F. Kennedy.

He restlessly crossed genres, trying out a screen printing, set design and even choreography.

Art was not a means to end. It may have brought him fame - most conspicuously when, in 1964, he became the first American to win the top prize for painting at the Venice Biennale - but he never rested on his laurels. Work was a never-ending project for a man who saw art as “a means to function thoroughly and passionately in a world that has a lot more to it than paint”.

Rauschenberg was a pivotal artist of his era. Among his best-known collaborators was his fellow Black Mountain artist Jasper Johns. They would offer each other ideas. The composer John Cage was inspired by Rauschenberg and his silent work (4' 33”) was apparently born out of contemplation of Rauschenberg's all-white series.

What Rauschenberg pioneered we take almost as commonplace today. But long before Damien Hirst was turning dead animals into sculpture, Rauschenberg had incorporated stuffed creatures into his creations; decades before Tracey Emin was parading her unmade bed, Rauschenberg had turned his pillow and quilt into a collage.

He was a titan whose ideas have been mined by ensuing generations. He was a herald of the conceptualism that still dominates the contemporary art world.

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