Experimental Research On Mechanical Properties And Frost-Resistance Of Hybrid Fibers Light-weight Aggregate Concrete

People dedicated to finding a kind of new material which was used to increase the ductility and toughness of the concert was added or substituted into the concrete substrate in order to improve the larger defects of concrete brittleness in long time. Many studies showed that light aggregate instead of gravel aggregates added into concert can improve the brittleness of concrete in some extent and also can increase the peak strain of the concrete along with the stress-strain curves was eased, however, the adding of fiber into the concert is a good method to increase the toughness of concrete and it also can obviously inhibit the development of internal crack existed in the concrete.In this paper, these two methods mentioned above were combined together in order to get better performance of concrete material.The rational use of lightweight aggregate and fiber not only can improve the brittleness of concrete but also can improve the performance of freeze-thaw resistance of concrete materials effectively. Domestic these related fields have been studied, but very little carbon-polyethylene hybrid fiber reinforced lightweight aggregate concrete was studied in detail and research about the fiber hybrid effect of durability of concrete,this paper makes up for this vacancy. By combination of regional advantages, this paper taking natural pumice largely existed in the region of Xilinhot in Inner Mongolia as light aggregate, the working performance, durability and mechanical properties of light-weight aggregate concrete mixed with carbon fiber and polypropylene fiber were studied in detail.The positive and negative hybrid effect of fibers and the quantitative relations of fiber volume ratio as well as its confounding effect on kinds of performance of concert were all explained by the definition of the enhancement (attenuation) coefficient and confounding coefficient and the hybrid coefficient calculation of the investigated parameters (the compressive strength, splitting tensile strength, mass loss rate, relative elastic modulus) of mechanics performance and durability also combined with the test result. The main reason caused positive, negative hybrid effect was analyzed and the confounding effect of mechanism of the different geometry fiber size in concrete was discussed, meanwhile, the relationship between velocity and intensity of concert was established by using ultrasonic detection method. The influence of fiber in concrete internal was investigated from the point view of wave velocity and the constitutive relation of hybrid fiber reinforced lightweight aggregate concrete were studied in order to more in-depth understand the influence of lightweight aggregate and hybrid fiber reinforced concert on concert material as well as the stress-strain curve was established. The results show that:the carbon fiber and polypropylene fiber in a reasonable range of dosage inside in concert can indeed produce good complementary effect and also can improve the performance of lightweight aggregate concrete, which can provide an effective way for the development of high-performance cement-based composite materials.