Evaluation of lightweight Concrete Core Test Including Steel Bars

In many steel reinforced concrete members, steel bars are not avoidable during concrete core drilling and the presence of these steel bars have a direct impact on the results of this test. This study aims to examine the effect of steel bars presence on the test results of recycled aggregate lightweight concrete (LWC) cores. For the purpose, one lightweight concrete mix was made with a total number of ۴۸ concrete cores were taken from a slab having the dimensions of ۱ m width, ۱.۵ m length and ۰.۱۵m thickness. Each core has the dimensions of ۹۰ mm in diameter and ۱۵۰ mm in height. Three different sizes of steel bars (۱۲, ۱۶ and ۲۰ mm) were used in six different locations (۲۵, ۴۵ and ۶۵ mm) from the base of the core and (۱۵ and ۳۰ mm) from the center line of the core. A recycled crashed clay brick (CCB) was used as an alternative to the coarse aggregate. Compare to the density of the normal concrete (۲۴۰۰ kg/m۳), the LWC was able to achieve nearly ۲۰% reduction of the total weight by fully replacing of normal aggregate with CCB. It has been found that the presence of the steel increases the compressive strength of the LWC cores. This effect is more noticeable when the location of the steel bar is near to the mid-height or the centerline of the concrete core. Also, the influence of the steel bar diameter has increased by increasing the size of the steel bar.

کلیدواژه ها:

Lightweight concrete ، Concrete core test ، Steel bars