Study on the High Temperature Performance of Fly Ash Based Geopolymer Concrete: FA30 retains about 80% of its compressive strength at 400 ° C

Research background and experimental design: Fly ash based geopolymer concrete is considered a sustainable alternative material due to its lower carbon footprint and better thermal stability than ordinary Portland cement (OPC) concrete. This study conducted experiments on residual mechanical properties, bond slip, shear friction, and microstructure after exposure to high temperatures ranging from 200 ° C to 800 ° C. Five levels of fly ash substitution were set at 0%, 20%, 30%, 40%, and 50%. The test contents included compressive strength, splitting tensile strength, stress-strain response, pull-out bonding behavior, and shear friction.

Key experimental results

The experiment showed that all geopolymer mixtures exhibited progressive degradation with increasing temperature, but the residual performance and thermal stability of the mixture with a fly ash content of 20% -30% were better.

. FA30 retains about 80% of its original compressive strength at 400 ° C, but its performance significantly deteriorates beyond 600 ° C. At 800 ° C, the elastic modulus decreases by about 85% -95%, and the peak strain increases significantly, indicating a transition from brittleness to ductility of the material under thermal exposure. Compared with conventional OPC concrete, the bond strength degradation of fly ash based geopolymer is smoother, and FA20 and FA30 exhibit better bond retention and lower slip values at high temperatures. SEM observation confirmed that the improvement of geopolymer heat resistance was mainly related to the formation of stable aluminosilicate gel network, the reduction of microcracks and the controlled pore development. The study also proposed regression based degradation models and bond slip models, which were validated with experimental data and existing literature.

The significance of polymer additives and building materials industry

Although this study focuses on concrete materials, its conclusions on the degradation law of performance and bond retention after high temperature have reference value for fire prevention, weather resistance, and structural safety assessment in the fields of construction and home decoration.

. In building material systems such as PVC profiles, sealants, and architectural coatings, the reasonable combination of weather stability, antioxidants, and light stabilizers is also the key to ensuring long-term performance; The phenomenon of smoother degradation of bond strength of geopolymer concrete at high temperatures also provides a comparative approach for the performance design of multi material interfaces under thermal exposure conditions. The degradation prediction model proposed in the study can provide a tool for post fire structural performance evaluation and support the potential application of fly ash based geopolymers in fire-resistant and sustainable structural systems.

Information source:Structural Characteristics of Fire‐Exposed Fly Ash Based Geopolymer Concrete， Organized by Herun Chemical.