Tinjauan Kembali Mengenai Pengaruh Modulus Kehalusan Pasir terhadap Kuat Tekan Beton

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ABSTRAK

Perancangan campuran beton memformulasikan bahwa kekuatan beton hanya ditentukan oleh faktor air-semen sedangkan modulus kehalusan pasir hanya mempengaruhi kelecakan beton segar. Modulus kehalusan pasir yang direkomendasikan SNI yaitu 1,50–3,50 dan pada ACI yaitu 2,40–3,00. Mengingat rentang modulus kehalusan pasir cukup jauh pada cara SNI/BS, dilakukan penelitian lanjut untuk mengetahui pengaruh perubahan modulus kehalusan pasir terhadap kuat tekan beton. Penelitian dilakukan dengan membuat campuran beton menggunakan cara Dreux, untuk kuat tekan rencana 30 MPa, slump rencana 80 mm, faktor granular ( ) 0,40, 0,45, dan 0,50, serta modulus kehalusan pasir 1,50, 2,00, 2,50, 3,00, dan 3,50. Hasil penelitian memperlihatkan sebaran kuat tekan aktual berfluktuaktif mendekati kuat tekan prediksi. Hal ini menunjukkan modulus kehalusan pasir tidak berpengaruh secara signifikan  terhadap kuat tekan beton. Hasil penelitian ini memperkuat perancangan campuran beton cara SNI/BS, ACI, dan lainnya seperti cara Dreux, yang beranggapan bahwa kuat tekan beton hanya dipengaruhi oleh faktor air-semen saja.

Kata kunci: SNI/BS dan ACI, kuat tekan beton, faktor air-semen, modulus kehalusan pasir ( ).

ABSTRACT

The concrete mix design states that the strength is only determined by the water-cement ratio, whereas the sand fineness modulus just affects the workability of fresh concrete. The sand fineness modulus in SNI is recommended about 1.50–3.50 and the ACI is about 2.40–3.00. Considering the ranges of sand fineness modulus is far enough in the SNI/BS, it is necessary to carry out further research to determine the effect of changes of sand fineness modulus on the concrete compressive strength. The Research is performed by making the composition of concrete mix using Dreux method, for the compressive strength design of 30 MPa, slump 80 mm, granular factor ( ) 0.40, 0.45, and 0.50, and the sand fineness modulus 1.50, 2.00, 2.50, 3.00, and 3.50. The results show that the distributions of actual compressive strengths scattered around the prediction of compressive strength. The results indicate that the sand fineness modulus does not affect significantly the compressive strength of concrete, even it does not affect the workability of fresh concrete. Thus this research reinforce concrete mix design theory of the SNI/BS and ACI method, which state that the compressive strength of concrete is only affected by the water-cement ratio.

Keywords: SNI/BS and ACI, concrete compressive strength, water-cement factor, sand fineness modulus ( ).