Experimental Research On Basic Mechanical Properties Of Recycled Concrete And Mortar With Aggregates From Different Sources

Recycled mortar and concrete is new building materials made of crushed concrete, and its application in practical engineering has far-reaching significance, not only protect the ecological environment, but also fully in line with national sustainable development strategies. Most research has focused on the influence of the replacement ratio of recycled aggregate, and the research of the influence of the sources of the recycled aggregate is still quite lacking. Therefore, the basic mechanical properties of recycled mortar and concrete with aggregates from different sources are mainly studied.The basic physical performance of recycled coarse and fine aggregate is studied in this paper to reveal the characteristics of recycled aggregate, which is used for mix proportion design. The results show that:as the increase of the compressive strength of original concrete of recycled aggregate, recycled aggregates both fine and coarse show higher apparent density, lower water absorption and lower crush value.Recycled aggregates made during the experiment are used to produce recycled mortar and concrete to study the influence of aggregates from different sources to the workability and the mechanical properties. The results show that:the recycled aggregates have little influence on the basic mechanic properties when their compressive strength of original concrete is similar. On the contrary, the recycled aggregates have considerable influence. However, the dispersion of the property of the aggregate from the top of the drilling pile is greater than the others, and the recycled concrete with the aggregate shows poorer mechanical property which indicates the influence of the aggregate source.According to the experimental results, the theoretical formula are established after analyzing the theoretical relationship between the properties and the original strength of concrete, including:compressive strength-original strength formula, tensile strength-original strength formula, flexural strength-original strength formula and constitutive model of stress-strain curve, which are used for assessing the influence of recycled aggregates to recycled mortar and concrete.