Crushed firebrick makes an excellent aggregate for a castable refractory, e.g. high heat refractory concrete. This type will survive in real high heat and can be used for hot-face1 applications
The mix of Firebrick Grog which is a refractory or heat resistant aggregate, mixed with a heat resistant cement, like Cement Fondu2, is often referred to as castable, which is suitable for making pizza ovens and other outdoor ovens.
I don’t want to disappoint but we are not experts on pizza oven, bread ovens or other outdoor ovens and don’t have the answers to questions about how best make such! - there is much online information and videos that will help you. We have no experience in making these ovens…yet…I want to give it a try one day!
The recommended mix of Firebrick Grog and Cement Fondu is 4 parts Grog to 1 part Cement.
Firebrick Grog is also suitable for the roman block method of mould making.
1 What is hot face?
Hot face is any surface facing the main heat generated by a heat source (e.g. wood fire, gas burner, electrical heating spiral & other heat producing elements.) Internal walls, floor and arches made from firebricks inside a pizza oven is hot-face. Firebricks face the heat, the hot flames from wood fire and the red hot embers. Refractory concrete can face the heat therefore applied as a hot face.
2 Cement Fondu is a Calcium Aluminate Cement (CAC) also known a High Alumina Cement (HAC) which has a number of specific properties, including; quick setting and excellent resistance to heat, thermal cycles and abrasion.