Fire-retardant gypsum solutions on exfoliated vermiculite were studied using volcanic ash and the multi-functional additive D – 5. It was revealed that the introduction of the D-5 additive by weight from the binder significantly speeds up the setting time of the composite gypsum solution on the expanded vermiculite. gypsum-vermiculite solutions with additives of Portland cement and D – 5 have a higher water resistance.The compositions of composite gypsum solution on exfoliated vermiculite and ash have been developed. It has been established that volcanic ash of a fraction of 0.0–0.315 mm can be replaced by expanded vermiculite without a noticeable increase in average density. Additives of Portland cement and D – 5 increase the strength of the gypsum composite vermiculite solution with ash, the softening coefficient of the composite increases to 0.75.

Keywords: gypsum, portland cement, expanded vermiculite, volcanic ash, additive D-5, fire protection, gypsum vermiculite solution, tensile strength at bending and compression, average density, softening coefficient