Pengaruh Soda Api Terhadap Karaktristik Beton Struktural Pada Pekerjaan Jalan

In this study using the addition of caustic soda to accelerate the hardening of concrete fc' 30 Mpa. Inspired by the people who live around the coast of Rupat Island, Bengkalis Regency where when casting concrete add soda fire as an additive to accelerate the hardening of the concrete, so it is not eroded and porous by sea water at high tide and low tide. This research was carried out with four specimens, where each specimen each made 3 cylindrical samples with a diameter of 15 cm with a height of 30 cm in a compressive strength test and a concrete beam sample with a height of 15 cm, a width of 15 cm and a length of 60 cm for testing the flexural strength. The variation of the addition of caustic soda for both types of samples is 1%, 1.5% and 2.5% with the age of concrete testing 7, 14, 28 and 56 days compared to normal concrete both compressive strength and flexural strength. From the research in the concrete compressive strength results obtained normal 29.44 MPa age 7 days, 29.84 MPa 14 days, 30.10 MPa 28 days, 30.68 MPa 56 days after the addition of soda soda 1%, 1.5% and 2 , 5% for ages 7, 14, 28 and 56 days, only one specimen fulfilled the compressive strength of concrete, namely the addition of 1% soda soda with a compressive strength of 30.59 MPa at 56 days. In the test of normal flexural strength of 7 days 3.64 MPa, 14 days 4.01 MPa, 28 days 4.56 MPa, 56 days 4.71 MPa, after the addition of caustic soda 1%, 1.5% and 2.5 % of the ages 7, 14, 28 and 56 days there are no concrete beam samples that can meet the expected flexural strength. The relationship between flexural strength and compressive strength on the immersion age of 7, 14, 28 and 56 days, then the resulting constant values are 0.62, 0.68, 0.76 and 0.80. The effect of adding caustic soda to speed up hardening of concrete has a negative impact on the flexural strength and compressive strength of concrete