Development of microstructure of early cement paste(0-6 h) was investigated with1H lowfield NMR.It was found that T 2(transverse relaxation time) distributions of fresh cement paste were bimodal and two peaks were ‘long component' and ‘short component'.Separation degree of two peaks was a sign of exchange of water within flocculation and outside flocculation.Factors such as water cement ratio,specific surface area and dosage of superplasticizer had influences on the separation degree: the separation degree increased with the water cement ratio;the separation degree of cement paste prepared with cement with a high specific surface area was zero;dosage of superplasticizer will decrease separation degree.Results also suggested that T2 distribution gradually moved to the left and T2 of long component and initial fluidity were linearly correlated.
