Value of Concrete Compressive Strength on 28 days with Variation of Candlenut Shell Applicated to Plate on a Non-destructive Test Using Hammer Test

Concrete compressive strength is one of the parameters used to control the quality of a concrete. Concrete compressive strength testing method which is considered the highest level of reliability is a destructive test using a compressive testing machine. Testing requires quite high costs and a longer processing time. But sometimes testing must be done in the scene. Based on the case, a testing tool is needed to measure or determine the compressive strength of concrete without spoil, which is known as the non-destructive test. The tool commonly used for this test is the hammer test. The type of research is experimental. The purpose of this research is to get the compressive strength value of a concrete plate variation of 30% candlenut shells from the test results using a hammer test so as the results can be close to the results of testing using a compressive testing machine (destructive test). The research variable is the testing method (3 point of testing with angle 0°), the age of concrete plate curing, the method of curing (wet curing and dry curing). The number of samples of reinforced concrete slabs is 8 pieces measuring 50cm x 25 cm x 12cm. The research results are Compressive strength of concrete slabs of 30% candlenut shell variations using a Hammer test showed that the concrete strength reached 23-27 Mpa both in wet curing and dry curing or equivalent to the quality of K250 concrete at 28 days. The results also indicate higher values compared to normal concrete slabs.