Lafarge SA, the world's largest building materials maker, will merge its cement business with Shui On Construction and Materials (Socam) in a US$650m joint venture, creating one of the top three companies in the Mainland's booming cement market, The South China Morning Post reported. Hong Kong-based Socam chairman Vincent Lo Hong-sui said Thursday he expected the merger of Paris-based Lafarge's four mainland plants with Socam's seven would return his company's loss-making cement business to profit next year. Lafarge Shui On Cement, to be 55% owned by the French firm and the remainder owned by Socam, will operate in a market that accounts for 45% of the world's cement consumption — or an estimated 900m tonnes last year, the newspaper said.