Turnover for the first six months grew by 7.5% to US$1,433.8m and the EBITDA advanced by 9.0% to US$279.5m. The aggregates-based business generated a turnover 7.5% ahead at US$1,122.3m to produce an 18.7% improvement in the trading profit to US$164.0m.  After a 10% increase in aggregates shipments in the first quarter, second quarter deliveries were some 6% higher, while average prices improved by around 2%.  Ready-mixed concrete deliveries were also ahead, boosted by strong housebuilding activity.  Blacktop volumes, on the other hand, suffered a decline in the second quarter because of reduced road expenditure in California and wet weather in Texas.  The benefits from higher volumes and prices in the division were partially offset by the cost of improvement and expansion at four important extraction sites as well as higher fuel and healthcare costs.  The chemicals division reduced its first half trading loss from US$15.2m to US$4.0m, but pricing remained weak for caustic soda.  Turnover was 7.6% higher at US$311.5m.  In the full year, the chemicals business is expected to broadly break even, while the profit from construction materials should continue to advance, as the outlook for aggregates demand remains good for the rest of 2004.