| High performance lightweight aggregate concrete(HPLC),with excellent workability and mechanical properties,can significantly reduce the dead load of the structure.It is suitable for infrastructures with low deadweight requirement and resistant to harsh environment,such as high-rise building,long-span bridge,offshore floating platform,etc.,which have great technical advantages and application potential.In this paper,the design requirements of HPLC were summarized.The influence of apparent density,flowability,mechanical properties and durability of HPLC were studied,based on the volume content of lightweight aggregate in concrete.On this basis,the mix proportion of HPLC was optimized to improve the pumpability,which expand the application breadth and height of HPLC.Finally,the ultra long-term properties of HPLC prepared from two types of solid waste lightweight aggregates with a service life of 14 years were experimentally studied.The feasibility of HPLC prepared from solid waste lightweight aggregates was confirmed.The main achievements are as follows:Firstly,the performance criteria of HPLC were summarized comprehensively,and the impact of lightweight aggregate volume content on the workability,mechanical properties,durability and volume stability of HPLC were studied.HPLC with low apparent density,great workability,high compressive strength,excellent durability and volume stability were prepared.Results show that the optimal volume content range of lightweight aggregate in HPLC was30～40vol.%.Secondly,HPLC with high flowability was successfully pumped to a high-rise building over 100 m,and the hardened properties test shown that it still met the performance criteria of HPLC.The relationship among water absorption,pressure and duration of lightweight aggregate was established,and the mechanism for flowability deterioration of HPLC during pumping was revealed by evaluating the change of free water content and pressure loss of HPLC during pumping.Thirdly,the mechanical properties,durability and microstructure properties of ceramic waste slag-based HPLC and furnace slag HPLC with a service life of 14 years were studied.The microstructure observation results shown that,compared with furnace slag lightweight aggregate,ceramic waste slag-based lightweight aggregate with rough surface can be closely combined with cement paste,which enhanced the microstructure of interfacial transition zone,thus improving the mechanical properties and durability of concrete.The feasibility and longterm durability of solid waste based HPLC were proved. |
