Would the US constitution be changed if the admendment received 2/3 of the popular vote.?
No. Popular vote has nothing to do with it. There are two methods: The first method is for a bill to pass both halves of the legislature, by a two-thirds majority in each. Once the bill has passed both houses, it goes on to the states. This is the route taken by all current amendments. Because of some long outstanding amendments, such as the 27th, Congress will normally put a time limit (typically seven years) for the bill to be approved as an amendment (for example, see the 21st and 22nd). The second method prescribed is for a Constitutional Convention to be called by two-thirds of the legislatures of the States, and for that Convention to propose one or more amendments. These amendments are then sent to the states to be approved by three-fourths of the legislatures or conventions. This route has never been taken, and there is discussion in political science circles about just how such a convention would be convened, and what kind of changes it would bring about.
