<![CDATA[Kualitas bata beton pejal abu vulkanik Merapi saat ini di B70 (rata-rata kuat tekan = 89,765 kg/cm2) yang berarti produk belum mencapai kualitas optimal B100 (kuat tekan ≥ 100 kg/cm2). Penelitian menggunakan desain faktorial 33 dan split split plot dilakukan untuk meningkatkan kualitas produk menjadi B100. Hasil penelitian menunjukan bahwa faktor A (kadar air pembentukan), faktor B (komposisi bahan), faktor C (gradasi butir agregat), interaksi faktor AB, interaksi faktor BC, dan interaksi faktor ABC berpengaruh secara signifikan terhadap kuat tekan. Kombinasi  faktor A level 2 (0,2), faktor B level 1 (1:5), dan faktor C level 1 (30% :30%:40%) meningkatkan kualitas produk menjadi B100 (rata-rata kuat tekan = 159 kg/cm2). Kata Kunci : Faktorial 33, split split plot, Bata Beton ABSTRACT Quality of solid concrete brick Merapi volcanic ash is in B70 (avarage of compressive strength = 89,765 kg/cm2) that means products haven`t reached the optimal quality B100 (compressive strength ≥ 100 kg/cm2). This research use 33 factorial design of experiments and split split plot to improve product quality into B100. The result of the research shows that A factor (water/cement ratio), B factor (material composition), C factor (gradation of aggregate), interaction of factor AB, interaction of factor BC, and interaction of factor ABC significantly affect to the compresissive strength. Combination A factor at level 2 (0,2), B factor at level 1 (1:5), and C factor at level 1 (30% :30%:40%) improve product quality into B100 (average of compressive strength = 159 kg/cm2). Keyword: 33 factorial, split split plot, compressive strength, concrete brick]]>
