I think you are grown up now that's why you are willing to quit that bad habit of eating cement.you have to understand very clearly that eating cement is only harmful to your health.this will cause indigestion , anemia , pain in your stomach, bleeding constipation etc.apart from that you may get infested with so many worms that may cause some serious and life threatening conditions . I can understand it's hard for you to leave this habit ..but it's not impossible if you are once determined enough to get rid of this harmful habit.you can use some chewing gums etc to divert your attention from cement.mainly it's up to you and your will power.