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Explosions, such as a bomb explosion and a gas explosion, can cause catastrophic damage on the buildings. In fact, an explosion may result in large dynamic loads, greater than the original design loads, of many structures. Two RC specimens were tested under explosive loading. The first specimen was used as a control for the experiment, while the other was retrofitted with 6 near surface mounted (NSM) Carbon FRP strips on each face. Both specimens were subjected to a 60g Pentolite at stand off distances of 0.6m. The aim of this experiment was to observe and compare the behavior of the two specimens, and their ability to resist blast loads respectively. Of particular interest was the response of the retrofitted RC specimens NSM Carbon FRP. The experimental results showed that NSM retrofitting with Carbon FRP is an effective way to provide extra strength when retrofitting against blast loading.

List The active of MgO was produced from magnesite tailings under certain conditions. The effect of calcinations temperature on the crystal structure of MgO was analyzed by XRD and SEM. Crystal particle of MgO was calculated according to Scherrer formula. The microstructural differences between the MgO agglomerates were examined by SEM at different temperatures. The activity of MgO was evaluated though conductivity which was measured by the conductivity meter. The activity of MgO effected by calcinations temperature was studied. The result showed that magnesite tailings was fully decomposed when that was calcined for 60min with the calcinations temperature of 1050°C, and the activity of MgO was very high. Established a hydration and expansion model of MgO is proposed to explain the activity of MgO.

To offer or predict the shear strength of compacted lime stabilized expansive soils after long-term immersion for the slope analysis, the paper carried out direct shear test on the compacted stabilized expansive soils after different immersion time. The test results show that long-term immersion has significant impact on the shear strength of the lime stabilized expansive soils, the shear strength reduced sharply after soaking, but the shear strength tends to a stable value about 60%~70% normal strength while soaking is longer than 50 days. Logarithm model can well fitted the sketch of φ, c and immersion times within 50 days, which may be used to predict the shear strength of the stabilized expansive soils quickly.

To offer or predict the shear strength of stabilized expansive soils after cyclic wetting and drying for the slope analysis, the paper carried out direct shear test on the stabilized expansive soils after different times of cyclic wetting and drying. The test results show: The first 3-5 times of cyclic wetting and drying will cause the shear strength decreased sharply, and after about 7-9 times of cycle, the shear strength will trend to a stable value, which is about 40-60% of the normal strength before the cycles. Logarithm model can well fitted the variation of the shear strength and the times of cyclic, so the shear strength index can be predicted by using the models which was established according to the test results.

With the development of the reform and opening and the market economy in China, numerous small-medium construction enterprises (SMCEs) gained many developing opportunities and challenges which never appeared before. To most SMCEs, they should continuously cultivate their core competitiveness, if they want to win wider space for development. Facing developing chances and challenges, they should also set a novel principle of management, involve special operation and coordination, and constantly absorb developing powers from innovation.

The research of large amplitude vibration of simply supported beams can be dated back to 1950; many achievements and some evolution were accomplished by many researchers over hundred and fifty years. The development of nonlinear vibration formulations for beams has gone through distinct phases–earlier continuum solutions, development of appropriate forms, extra-variational simplifications, debate and discussions, variationally correct formulations and finally applications. A review of work in each of these phases is very necessary in order to have a complete understanding of the process of evolution of this field. This paper attempts to achieve precisely this objective.

For the analysis and design of RC structures, there is a fundamental assumption that the strain in an embedded reinforcing bar is the same as that in the surrounding concrete. Therefore, bond forces must be developed on the interface between concrete and steel, such as to prevent significant slip from occurring at the interface. An end anchorage may be considered reliable if the bar is embedded in to concrete a prescribed distance known as the development length of the bar. If in the beam the actual extended length of a bar is equal to or greater than this required development length, no premature bond failure will occur. Research has indicated that the development length was influenced by tensile strength of concrete, surface and diameter of bar, cover distance, bar spacing, transverse reinforcement, and other factors. Current design methods in different countries’ Codes, attentions are directed toward providing adequate length of embedment, which will ensure development of the full strength of the bar.

Recycled fine concrete aggregate can not be directly used for concrete for its large water absorption, so we get recycled concrete powder through grinding process, and carried out series experimental studies on the recycled concrete powder. The results show that the technical parameters of recycled concrete powder can achieve the requirements of S95 grade slag powder. The slump constant of recycled concrete mixed with recycled concrete powder is slightly less than slag concrete,while cohesiveness and water retention is better than slag concrete. Replace slag powder with recycled concrete powder, the recycled concrete has high early strength but post-intensity does not change significantly. Recycled concrete powder replacement slag powder does not reduce the impermeability, frost resistance and carbonation resistance of recycled concrete. The conclusion shows that recycled concrete powder can completely replace slag powder in concrete to realize full efficiency reuse of waste concrete.

An explosion is defined as a large-scale, rapid and sudden release of energy. Explosions, such as a bomb explosion within or immediately nearby a building and a gas-chemical explosion, can cause catastrophic damage on the building's frames, collapsing of walls, blowing out of large expanses of windows, and shutting down of critical life-safety systems. In fact, an explosion may result in large dynamic loads, greater than the original design loads, of many structures. Blast phenomenon and blast efforts have been made during the past several decades to develop methods of structural analysis and design to resist blast loads. The analysis and design of structures subjected to blast loads require a detailed understanding of blast phenomena and the dynamic response of various structural elements. This paper introduces different methods to estimate blast loads, also presents a comprehensive overview of the effects of explosion on RC structures.