Tests are carried out to compare post-install pull-out force and compressive strength of concrete at different strengths and different curing ages and main test and research results are obtained for examination of concrete strength measuring curve by post-install pull-out method.The strength measuring curve may be used when concrete strength meets certain conditions.

This article in view of the first-class highway service performance and the present highway construction quality testing evaluation content and the method,unifies the anti-slippery question which in the road use exists,proposed improves the road surface skid-resisting capability appraisal status in the highway maintenance management the importance and the feasibility.

Concrete segments are the main structures of shield tunnel,they are also the comprehensive performance guarantees of waterproof,fireproof and durability.Therefore,the overall performance of the segment has a high requirment.But the large-diameter concrete segment in the production sometimes happens more bubble,thus it is easy to form leakage channels,which affects the durability.In this paper,concrete materials,mix design,mould,mold release agents,vibration technology and other aspects attempt to reduce the segment bubble,as a result,good results are gotten in the practice production.

Technological and economical feasibility through scatter-filling the recycled aggregate (RA) into the high fluidity concrete to realize recycling and reusing the waste concrete in worksite has been investigated in this paper.The results showed that the uniformity and the compressive strength of the hardened concrete at 3 and 28 days is obviously improved through scatter-filling the RA with higher compressive strength than that of the hardened high-fluidity concrete.While the compressive strength of the origin concrete is obviously lower than that of the hardened high-fluidity concrete and the volume percent of the RA scatter-filled is less than 30% ,compressive strength at 3 days and autogenous shrinkage of the highfluidity concrete can also be obviously enhanced,and the strength at 28 days is also improved.However,scatter-filling more than 40% of the RA will result in decrease of the strength at 28 days.It is also found that it is economic by scatterfilling the RA into the high-fluidity concrete,as compared to that without scatter-filling or scatter-filling with the natural aggregate.

Effect and mechanism of novel AS interfacial agent on the bonding strength of fresh-old concrete under natural curing condition were investigated in this paper.The results showed that under natural curing condition,compared with the treatment with low water-cement-ratio cement paste(LWC),the bonding strength at early curing age by using the novel interfacial agent was relatively lower,and was just as comparable to that without interfacial treatment.However,the bonding strength showed decrease after curing for 7 days while using LWC as interfacial agent or without treatment;while using the novel interfacial agent,the increase of its bonding strength is related to the components of the interfacial agent.The bonding strength also showed decrease after 28 days while using the novel interfacial agent with silica fume as the main component.When fly ash was used as main component,the bonding strength showed a continuous increase within 56 days.The main reason was that shear stress was formed due to big deformation difference between the old and the fresh concrete,which resulted in partial destruction of the early-formed adhesion.On the other hand,when novel interfacial agent with fly ash as the main component was used,its adhesion was formed slowly with the prolongation of the curing time.As a result,the bonding strength of the interface can be increased continuously.

研究了地铁管片用高性能混凝土的表面强韧化方法,在优化混凝土搅拌工艺、调控骨料水泥石界面过渡区微观结构、提高混凝土强度基础上,采用聚合物水泥混凝土对普通水泥混凝土进行表面强韧化处理.结果表明,采用掺合料裹骨料工艺可有效提高混凝土强度,采用不同厚度的聚合物水泥混凝土进行表面处理,对混凝土劈裂抗拉强度影响不大,但可有效增强其变形能力和表面抗冲击韧性.