SELF-COMPACTING LIGHTWEIGHT CONCRETE WITH PARTIAL SUBSTITUTION OF PUMICE STONE AS COARSE AGGREGATE AND DIATOMITE AS CEMENT REPLACEMENT

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ABSTRAK

Self-Compacting Lightweight Concrete (SCLC) merupakan beton yang mengombinasikan kemampuan memadat sendiri dengan bobot ringan. Penelitian ini mengevalusasi pengaruh substitusi batu apung (50%) pada agregat kasar dan substitusi diatomit sebesar (5%, 10%, 15%, 20%) pada semen terhadap sifat segar, berat jenis, dan kuat tekan beton. Desain campuran menggunakan kombinasi metode Okamura dan SNI 03-2834-2000. Pengujian meliputi slump flow, berat jenis, dan kuat tekan umur 28 hari. Didapatkan hasil bahwa batu apung efektif menurunkan berat jenis, sedangkan diatomit meningkatkan kuat tekan melalui reaksi pozzolanik, namun kadar diatomit yang berlebihan menurunkan integritas kinerja struktural. Kombinasi optimal yang diperoleh adalah substitusi batu apung 50% dengan diatomit 5%, dengan kuat tekan 22,61 MPa serta berat jenis 1922 kg/m³, sehingga berpotensi digunakan sebagai beton ringan struktural.

Kata kunci: Self-Compacting Lightweight Concrete, batu apung, diatomit, kuat tekan, berat jenis

ABSTRACT

Self-Compacting Lightweight Concrete (SCLC) is concrete that combines self-compacting properties with light weight. This study evaluates the effect of pumice substitution (50%) in coarse aggregate and diatomite substitution (5%, 10%, 15%, 20%) in cement on the fresh properties, density, and compressive strength of concrete. The mix design utilised a combination of the Okamura method and SNI 03-2834-2000. Testing included slump flow, density, and compressive strength at 28 days. The results showed that pumice effectively reduced density, while diatomite increased compressive strength through pozzolanic reactions; however, excessive diatomite content reduced structural performance integrity. The optimal combination obtained was a 50% substitution of pumice with 5% diatomite, with a compressive strength of 22.61 MPa and a density of 1922 kg/m³, making it potentially suitable for use as structural lightweight concrete.

Keywords: SCLC, pumice, diatomite, compressive strength, density