WASHINGTON (AP) — President Donald Trump played White House tour guide on Wednesday, showing off the helipad he is building on the lawn before leaning over to autograph a piece of it and bragging about the ballroom he’s rushing to complete despite legal challenges.Trump gushed for several uninterrupted minutes about granite being laid and said the chopper landing area would leave visiting foreign leaders “very impressed” — including Chinese President Xi Jinping, who is coming next month.At times, he sounded almost like a construction manager, singing the praises of granite over asphalt in painstaking detail and noting for reporters he brought out for the show that the stone could withstand 35,000 pounds per square inch of pressure. “That’s stone that, if you took a hammer and you started hammering right now — all day long — you wouldn’t see a mark on it, literally, that’s the kind of power it is,” Trump said, at times straining to be heard over the thrum of ongoing work behind him. The president also revealed for the first time that he has replaced the walkway from the White House’s diplomatic entrance along with a portion of the asphalt driveway around the South Lawn with white granite.“One thing I know how to do is build,” he said, asserting that asphalt is “not appropriate for a great house, or a great place like the White House.” He said that, had he instead merely used “really powerful concrete,” it would have supported ”just a tiny fraction of that in terms of strength.”