Study On The Pumping High-strength Light-weight Aggregate Concrete

The lower density and higher strength are the most obvious characteristics of lightweight aggregate concrete (LWAC). This new material has significantly economic and social value when it is applied to some special projects such as large-span bridges and high buildings. LWAC is becoming one of the important trends in the development of modern concrete.To solve the problems such as poor workability, large shrinkage value and crack easily of LWAC, on the basis of systematic experiments, the author establishes LWAC workability evaluation system and advances the testing method of pumping performance of LWAC; the control technology of discrete of LWAC is introduced through analyzing structure formation process and establishing the mathematic model; based on studying the strength source of LWAC and the function mechanism of artificial additive, this paper not only confirms some major factors which affect concrete strength but explores the preparation technology route of high strength LWAC; the different effects of several fibers in LWAC have been studied, and the fiber is introduced in pumping LWAC to improve its crack-proof performance. Moreover, the good crack-proof performance CL40-CL60 fiber-reinforced pumping LWAC is prepared through mixing up superplasticizer, artificial additive, fiber, and adopting other technologies. This kind of LWAC is also successfully applied to Caidian Han River Bridge Project that reduced the cost, shortened the construction period and archived great economic benefit.The facial and pore properties of lightweight aggregate and transition zone of LWAC is studied by the means of SEM and XRD. It is concluded that the "embedded" transition zone of lightweight aggregate-paste makes the principle contribution to the higher early strength of LWAC. Meanwhile, the "internal curing" of the double pore structure in LWAC has been proved.