Expanded Clay Foam Concrete (eC-FC) is a light-weight foam concrete with expanded clay aggregates, which is an important class of building materials, yet its tensile strength $f_t$ and fracture toughness $K_{IC}$ cannot be easily measured using small test samples due to its highly heterogeneous microstructures. This study presents a simple closed-form model for quasi-brittle fracture of heterogeneous solids confirmed by comprehensive three-point-bend (3-p-b) test results from 168 notched eC-FC specimens with eight group sample designs. One tensile strength $f_t$ was determined from individual group or all from the model initially developed for normal concrete, proving both the trans-granular fracture in eC-FC and inter-granular fracture in normal concrete can be modeled by this fracture model. Unidirectional compressive tests of the eC-FC were also performed, and tensile strength $f_t$ estimated from the compressive strength $f_c$ is consistent with $f_t$ from 3-p-b tests. Fracture toughness $K_{IC}$ was determined from the model using tensile strength $f_t$ and the average aggregate size G.

膨胀黏土泡沫混凝土（eC-FC）是一种具有膨胀黏土骨料的轻质泡沫混凝土，是重要的建筑材料类别，但其抗张强度 $F_{Ť}$ 和断裂韧性 ${ķ}_{\mathrm{一世}C}$由于其高度异质的微观结构，因此无法使用小型测试样品轻松测量。这项研究提出了一个简单的封闭形式的准均质脆性非均质固体破裂模型，该模型已通过168个带缺口eC-FC样品和八组样品设计的全面三点弯曲（3-pb）测试结果得到了证实。一抗拉强度$F_{Ť}$是从单个组或全部从最初为普通混凝土开发的模型确定的，证明了eC-FC中的跨晶断裂和普通混凝土中的晶间断裂都可以用该断裂模型进行建模。还进行了eC-FC的单向压缩测试，并且拉伸强度$F_{Ť}$ 由抗压强度估算 $F_C$ 和......一致 $F_{Ť}$来自3-pb测试。断裂韧性${ķ}_{\mathrm{一世}C}$ 由模型使用拉伸强度确定 $F_{Ť}$ 和平均总大小G。