Tujuan penelitian ini untuk, (1) mengetahui pengaruh fly ash sebagai pengganti sebagian agregat halus dan penambahan foam terhadap kuat tekan bata beton ringan foam, (2) mengetahui pengaruh fly ash sebagai pengganti sebagian agregat halus dan penambahan foam terhadap berat jenis bata beton ringan foam. (3) mengetahui pengaruh fly ash sebagai pengganti sebagian agregat halus dan penambahan foam terhadap daya serap air bata beton ringan foam (4) mengetahui persentase fly ash dan foam untuk mencapai kuat tekan bata beton ringan foam sesuai  SNI 03-0349-1989,  (5) mengetahui  persentase  fly ash  dan  foam  untuk mencapai berat jenis bata beton ringan foam (6) mengetahui persentase fly ash dan foam untuk mencapai daya serap air bata beton ringan foam sesuai SNI 03-0349-1989, (7) menghasilkan suplemen bahan ajar tentang kuat tekan, berat jenis dan daya serap air bata beton ringan foam pada mata kuliah Teknologi Beton.
Penelitian ini menggunakan metode kuantitatif eksperimen dan teknik analisa data menggunakan analisis regresi berganda. Variabel yang mempengaruhi dalam penelitian adalah (1) variabel terikat: kuat tekan, berat jenis, dan daya serap air bata beton ringan foam, (2) variabel bebas: penggunaan fly ash dengan variasi 0%, 25%, 50%, dan 75% terhadap kebutuhan agregat halus dan variasi penambahan foam 20% dan 40% dari volume beton.
Berdasarkan hasil penelitian disimpulkan bahwa, (1) penggunaan fly ash dan foam berpengaruh sangat kuat terhadap kuat tekan bata beton ringan foam, (2) penggunaan fly ash dan foam berpengaruh sangat kuat terhadap berat jenis bata beton ringan foam, (3) penggunaan fly ash dan foam berpengaruh sangat kuat  terhadap daya serap air bata beton ringan foam, (4) pada komposisi 25% fly ash 20% foam dan 75% fly ash 20% foam memenuhi kuat tekan mutu IV dengan masing-masing nilai sebesar 3,974 Mpa dan 3,632 Mpa, pada komposisi 50% fly ash 20% foam memenuhi kuat tekan mutu III dengan nilai sebesar 6,196 Mpa, (5) semua komposisi memenuhi syarat berat jenis bata beton ringan foam, (6) pada komposisi 0%-50% fly ash 40% foam memenuhi daya serap air mutu II, pada komposisi 0%-75% fly ash 20% foam dan 75% fly ash 40% foam memenuhi daya serap air mutu I, (7) bahan ajar yang dihasilkan berupa suplemen bahan ajar mata kuliah Teknologi Beton.

Kata kunci: fly ash, foam, bata beton ringan foam, kuat tekan, daya serap air.

The purpose of this research are, (1) determine the effect of fly ash as a partial replacement for fine aggregate and added foam to the compressive strength of lightweight concrete brick foam, (2) determine the effect of fly ash as a partial replacement for fine aggregate and  added foam to the density of lightweight concrete brick foam, (3) determine the effect of fly ash as a partial replacement for fine aggregate and added foam to the water absorption of lightweight concrete brick foam, (4) determine the percentage of fly ash and foam to reach a compressive strength lightweight foam concrete brick according to SNI 03-0349- 1989, (5) determine the percentage of fly ash and foam to reach a density of lightweight concrete brick foam, (6) determine the percentage of fly ash and foam to reach a water absorption  lightweight foam concrete brick according to SNI 03- 0349-1989 (7) supplement module or teaching materials on compressive strength, density and water absorption of concrete brick lightweight foam on the course Concrete Technology.
This study uses quantitative method by techniques experimental, data analysis  used  multiple  regression  analysis.  Variables  in  the  study  are  (1) dependent variable: compressive strength, density, and water absorption of lightweight concrete brick foam, (2) independent variables: the use of fly ash with a  variation  of  0%,  25%,  50%,  and  75%  to  the  needs  of  fine  aggregate  and variations addition foam 20% and 40% of the concrete volume.
Based on the results of the study are concluded that, (1) the use of fly ash and foam very strong influence on compressive strength of lightweight concrete brick foam, (2) the use of fly ash and foam very strong influence on density of lightweight concrete brick foam, (3) the use of fly ash and foam very strong influence on water absorption of lightweight concrete brick foam, (4) the composition of 25% fly ash, 20% foam and 75% fly ash, 20 % foam got quality IV compressive strength with value 3.974 Mpa and 3.632 Mpa; the composition of 50% fly ash, 20% foam got quality III compressive strength with a value of 6.196 Mpa, (5) all  composition fulfill of density lightweight foam concrete brick, (6) the composition of 0% -50% fly ash, 40% foam got quality water absorption II, the composition of 0% -75% fly ash, 20% foam and 75% fly ash, 40% foam got quality water absorption I, (7) teaching material or module generated in the form of as a supplement teaching materials course Concrete Technology.

Keywords: fly ash, foam, brick lightweight foam concrete, compressive strength, water absorption.