Papers by Author: Shu Hua Liu

Abstract: The activity index of steel slag-GGBS composite mineral admixture with different steel slag contents at the W/B of 0.3, 0.4, and 0.5 was investigated. The results show that the activity index of the composite mineral admixture with higher GGBS content is larger, and this phenomenon is more obvious at later ages. At lower W/B, the gap of activity index of different composite mineral admixtures is smaller. The activity index of each composite mineral admixture is higher at lower W/B and at later age. The steel slag-GGBS composite mineral admixture is more suitable to be used in high strength concrete than in low strength concrete. As far as the long-term properties of concrete are concerned, the activity index of the composite mineral admixture at the late age should be adopted.

Abstract: Congregation of the human activities, changes of the environment and weakening of the ecological capacity, prompts the emergence of new development concept. In order to adapt the development need, Ecological livable cities becoming a new pattern in the 21st century. This article puts forward with the significance of the construction of ecological livable city, analyses the achievement and problem of the construction of ecological livable cities in Nanning, and some methods and countermeasures are also proposed. Obviously, the ecological livable city is regarded as a key and direction for the development of Nanning in the future.

Abstract: The effect of glass powder on strength and microstructure of ultra high performance cement-based materials was investigated in this paper, which aimed to provide an additional option for glass recycling and potentially reduce the high costs of this kind of materials. Compressive strength of pastes and mortars with different glass powder content were tested and their microstructure properties were analyzed by scanning electron microscopy (SEM). Test result showed that the compressive strength rose initially with the increase of the amount of glass powder, and reached to the peak at 20% replacement ratio, then decreased a little. The glass powder in ultra high performance cement-based materials had exhibited pozzolanic reaction and filling effect, contributing substantially to strength increase. In addition, no ASR micro-cracking ring was found around the large glass powder particle due to the enough fineness of glass powder and the existing of silica fume.

Abstract: In this testing research, a series of High Performance Recycled Aggregate Concrete (HPRAC) with recycled aggregate were prepared and their mechanical behaviors were tested, especially uniaxial compressive stress-strain behavior. The influence of the recycled aggregate replacement on mechanical behaviors of HPRAC was studied by changing replacement ratio of recycled aggregate. Testing results show that the strength of HPRAC decrease a little with the increase of the content of recycled aggregate; the uniaxial compressive stress-strain curve of HPRAC is similar to that of ordinary concrete, and the ductibility of HPRAC improve with the increase of the content of recycled aggregate; the fitted regression curves (especially numerical model) approach to measured curves and can be used in constitutive relations analysis for concrete structure.

Abstract: This study has investigated the controlling ASR with high quality I class fly ash. The results show that the content of fly ash is more important than the quality of fly ash for the effect on preventing ASR. The solubility of alkali in fly ash has been studied in various alkali concentration solutions. The mechanism of a low content of fly ash accelerating swell of concrete but a high content of fly ash controlling swell is discussed for controlling ASR with fly ash contained high alkali content.

Abstract: In order to establish a mathematic model of the autogenous deformation of concrete incorporating MgO as expansive agent, we study the characteristics of it. Based on the results of testing researches and testing data, we get a mathematic model, which can clearly reveal the characteristics of autogenous deformation of concrete incorporating MgO as expansive agent. Autogenous deformation of concrete incorporating MgO as expansive agent is steady, the expansion is not infinite and there is no retrogress. Age mainly influences the basic equation of autogenous deformation. The content of MgO (or fly ash) and temperature will magnify (or reduce) the deformation.

Abstract: As high strength concrete (HSC) is widely used in construction, more and more attention has been paid to crack resistance of it. In order to improve crack resistance of HSC, we study the influence of mineral admixtures (ground slag, silica fume and fly ash) on brittleness and characteristic length as crack resistance’ indexes. Testing researches shows, without admixture, crack resistance of HSC is the lowest; when one of the three mineral admixtures added, crack resistance increases dramatically; when two of the three mineral admixtures are added in the concrete, crack resistance increases a little more and it does not change very much no matter which two are mixed; crack resistance comes out the highest when the three mineral admixtures are added in concrete. Mechanism analysis shows, Adding fine and high active ground slag, silica fume and fly ash into concrete can greatly improve microstructure of transition zone, decrease Ca(OH)2, ettringite and porosity in concrete, increase C-S-H gel and greatly reduce the original micro-cracks in the transition zone.