Cement quality is directly related to construction quality and its duration, so the control of cement quality is a crucial link for concrete mixing plant. However, today’s cement industry is in a mess, and the unqualified quality is common. Clinker in cement is far less than the standards. “Small cement” can not be called as cement, and it is just abrasive powder. Regulation on cement is in heavy deficiency. Just depending on inspection strength, setting time and the stability is not enough.

1. Clinker: calcium silicate minerals are not less than 66%, and the ratio of calcium oxide and silicon oxide is not less than 2.0, which are regulated in standards. But these data are often unqualified in cement factories that often do the strength test.

2. Clinker quantity: the common cement clinker and gypsum content should be between 80% and 95%. However, clinker content is just around 65%-70% even in big cement factories, not to mention the smaller cement factories. According to a survey, the clinker content in smaller factories is just around 50%.

3. Detection methods: supervised by technical administration, cement is sampled once in a year, which can not constrain cement production. National inspection standards just include strength, setting time, soundness and some chemical indicators, which are far enough.