If only Honest Abe could manage a smile as he gazes from his perch at his memorial in Washington, DC. Why would Mr. Lincoln be pleased? Because 7 1/2 acres of specially tinted concrete were poured to form the new Reflecting Pool which lies between the Lincoln and World War II memorials in our nation's capital. The new pool replaces the old, cracked and polluted pool which had become both an eyesore and health hazard for the legions of tourists who visit the area each year. Park Service officials also noted that with its new tinted bottom, the pool will be more reflective - another bow to concrete's superior versatility.