Based on the chord-length density functions from the field of statistical physics, this contribution introduces a quantitative approach to estimate the distribution of cement paste thickness between neighboring aggregate grains in cementitious composites.

The slump of fresh concrete depends on three parameters——nominal water-cement ratio of concrete,average paste thickness of aggregates and fly ash-binder ratio.

Based on the calculation methods of nominal water-cement ratio of mortar and average paste thickness of standard sand provided by authors, the nonlinear relation between fluidity of mortar and nominal water-cement ratio of mortar, average paste thickness of standard sand, fly ash-binder ratio was established by using artificial neural network(ANN).

Taking concrete cost as an optimization aim,ensuring the concrete slump,28d compressive strength and chloride ion diffusion coeffi-cient to meet the design requirements,a less paste and lower-cost concrete mix proportion can be obtained by reasonably adjusting the average paste thickness,small coarse aggregate to coarse aggregate ratio and sand fraction.

Relationship among self-desiccation shrinkage and relative density of pastes,average paste thickness of aggregate on high performance concrete at early age;

Based on the calculation methods of equivalent water-cement ratio of concrete and average paste thickness of aggregates provided by authors,the nonlinear relation between 28 d concrete compressive strength and equivalent water-cement ratio of concrete,average paste thickness of aggregates,fly ash-binder ratio is established by using artificial neural network.

So oil migration-accumulation stage in storage layer can be judged by studying sands thickness of oil migration-accumulation.