Abstract. SNI 2493:2011 is the Indonesian National Standard containing the procedures for the manufacture and maintenance of concrete specimens in the laboratory. This standard regulates the way that compaction of compressive specimens is performed using internal vibrators in addition to manual compaction. Unfortunately, the amount and duration of vibrator compaction using an internal vibrator are not specified in the standard. This study examines the effect of vibrator duration when using an internal vibrator to compact concrete compressive strength specimens. The specimens used are of cylinders with diameter 15 cm and height 30 cm. 30 specimens were formed by each of the three concrete compaction methods used. The first type is where concrete is compacted manually by a tamping rod, 25 times each layer. The tamping rod is of 16 mm diameter and 62 cm height. The second type is compaction is by using internal vibrator, with 3 compactions per layer, each for 2 seconds. The third type also uses the internal vibrator, except the duration of each compaction is for 5 seconds. The results of compressive strength tests show that the compressive strength of the concrete compacted with the internal vibrator is about 10% higher than when manually compacting the concrete using a tamping rod. This proposed compaction of concrete by using an internal vibrator can be used as an alternative to manual compaction in the manufacture of concrete compressive strength specimens.
BackgroundConcrete is used in many civilian buildings, with or without other materials such as wood and steel. Building structures made of concrete have many advantages; high compressive strength, resistance to high temperatures, and flexible design. Concrete materials generally consist of cement, crushed stone, sand, water, and admixture. The key mechanical property of concrete used in structural planning is the compressive strength. The compressive strength of concrete is influenced by many things, including the physical properties of the constituents (i.e. crushed stone, sand, and water), mixing quality, density, curing, capping method, test method, and technician quality.