THE PROMISING POTENTIAL OF SIDOARJO HOT MUD AS ADDITIONAL MATERIAL FOR CONCRETE LINING PRODUCTION

The Lapindo hot mud in Sidoarjo, Indonesia (Lusi) has caused a detrimental effect on the environment and the community for more than 10 years. On the bright side, the waste mud contains a high amount of silica (SiO2) which makes it promising to be used as a concrete mix. This study tests the use of Lusi as an additive material in concrete lining production to reduce the use of sand. The standard of concrete lining considered is the national standard of Indonesia (SNI 03-4804-1998) for K250 concrete. Experiments were carried out using a mixture of Lusi 0%, 5%, 15%, and 25% of the weight. The results of the analysis of variance demonstrated an F-statistics of 173.883 with a significance value of 0.000 (< 0.05). This means that the compressive strength between concrete samples based on each percentage of the Lusi mixture is significantly different. Furthermore, the regression analysis demonstrates a staggering R-square value of 0.9999, which shows that the addition of Lusi material greatlaffectsct the compressive strength of the concrete. The addition of Lusi material greatly affects the decrease in the compressive strength of the lining concrete. The average compressive strength of concrete based on the addition of Lusi material of 0%, 5%, 15%, and 25% are 347.15 kg/cm², 297.85 kg/cm², 209.68 kg/cm², and 145.04 kg/cm², respectively. Therefore, it is concluded that a 5% addition of Lusi material is the most recommended level of Lusi material. This finding can be considered a solutive idea for managing the Lapindo mudflow disaster, which can also bring economic advantage in the production of the concrete lining by minimizing the use of sand.