Bleeding Concrete

Answer is from: http://wiki.answers.com When concrete is excessively vibrated (ie for a longer time than the recommended time) water tends to get segregated and starts appearing on the surface. This is 'bleeding' on setting, a layer of cement is formed on the top. This is to be scrapped or it may break in flakes due to some impact or brushing operations etc. Obviously a part of cement is lost and the resultant concrete is not of the quality - which it was meant for. >> I would add that brooming the top of the pour, if you notice bleeding, may help, depending on weather.