This paper presents a numerical scheme to estimate a residual fatigue life of damaged RC bridge decks by means of the pseudo-cracking method proposed, which converts crack inspection data into the on-site mechanistic damage of structural concrete. First, crack information, which can be obtained through a simple visual inspection at site, is transformed to equivalent strain fields upon a finite element discretization, and an equivalent damage state is numerically reproduced. Then, the proposed system simulates subsequent responses to assess the residual fatigue life despite the initial cause of the cracks. The methodology proposed in this study was examined by re-producing several inspection processes computationally, and the numbers of traffic load passages at failure is verified without using the past loading history. For engineering verification, the fatigue-loading experiment of RC slabs, which was taken from a bridge subjected to the real traffic loads, are targeted to be simulated by the pseudo-cracking approach. Sensitivity analyses are also conducted to compute the S-N diagram of the damaged slabs in the five deterioration grades specified by the JSCE maintenance code, and the quantitative results are found to approximately match the specified recommendation. This study indicates that the proposed approach is capable of leading crack strain fields of RC slabs to remaining life-span simulation of damaged RC for the case of low intensity and high cycle fatigue actions.

In order to study the influence of large size aggregate on self-compacting rock-filled concrete, the compactness between self-compacting concrete (SCC) and rocks, as well as the whole workability of self-compacting rock-filled concrete, the experimental test in the present paper was carried out on the 500-ton electro-hydraulic serve testing machine and the sizes of specimens are 450mm×450mm×450mm and 450mm×450mm×900mm. The results show that the exterior damage of self-compacting rock-filled concrete specimens are different from that of standard concrete specimens; the damage sections are flat and rocks are cut through in some areas, which shows mainly bond failure at interfaces between self-compacting concrete (SCC) and rocks. The compactness inside is well and the strength of self-compacting rock-filled concrete can almost reach that of SCC, which provides theoretical basis for the application of self-compacting rock-filled concrete.

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Rock-filled concrete (RFC) is an innovative dam construction material that has been developed quickly in China since 2003. The concrete is produced by pouring the Self-compacting concrete (SCC) into the voids of large rock chunks, with a minimum size of 300 mm, in a formwork. To date, all the practical applications have shown that using RFC in dam constructions has significant economic and environmental benefits. Total construction cost is reduced due to using large amount of rock chunks, which can amount to roughly 55% of the total volume of RFC. When producing SCC, we make full use of local raw materials (e.g. fly ash, limestone) and optimize mix design based on the simple mini-slump flow tests on pastes to obtain better workability and lower cost. SCC with excellent workability can be obtained even the powder material is limestone powder alone. It is indicated that RFC is a potential and promising material for use in future concrete dams.

Self-compacting rock-fill concrete with natural and recycled aggregate can be applied in large structural components’production. According to the deep analysis of material's mechanical properties test data, the author makes a study on the strength mechanism of the concrete material. The results show that the concrete material essentially is concrete, and the concrete strength of large-sized natural aggregate and recycled aggregate are basically the same. However, due to the varieties in material production process and material shape as well as the influence of the mechanical properties and aggregate size, the strength mechanism of them is different. Effective control on mechanical properties of self-compacting rock-fill concrete and aggregate's appearances and shapes is helpful to the strength design of the self-compacting rock-fill concrete with large aggregate.