Under the directives of the RILEM Technical Committee 294-MPA, this publication reports on the findings of an interlaboratory study that tested fiber-reinforced GGBFS-based alkali-activated concrete (FRAAC), with participants from Belgium, India and Slovenia. The research also elaborates prediction models for the tensile splitting strength of GGBFS-based FRAAC. This research endeavoured between 2020 and 2024 to find a globally reproducible FRAAC mix that could attain the required mechanical strength and workability criteria. The primary goal of the interlaboratory study was to generate FRAAC without the use of superplasticizers in order to maintain an S4 class consistency slump and achieve the desired 28-days cube compressive strength of 40 MPa. Steel and PVA fibers were determined to be incorporated to the GGBFS-based AAC mix at 0.3 and 0.1% volume fractions, respectively, through iterative interlaboratory investigations. Experimental program was conducted to examine the compressive and tensile splitting strength of these FRAAC combinations at different curing ages, ranging from 1 to 720 days. The findings indicate that while there were a few interlaboratory variations in the mechanical properties, the FRAAC produced was uniform across all participants. The desired compressive strength of 40 MPa was attained by GGBFS-based FRAAC with both steel and PVA fibers at 28 days. Although FRAAC containing steel fibers exhibited the higher early compressive strength, FRAAC prepared with steel and FRAAC prepared with PVA both demonstrated a 720-days compressive strength of about 61 MPa. The FRAAC mixes with steel fiber additions exhibited a tensile splitting strength that was approximately 30% higher than the mix with PVA fibers. Nonetheless, at all ages, the tensile splitting strength of both FRAAC mixes was clearly higher than 2 MPa. These results support reliable and consistent experimental findings, which allude towards FRAAC as a sustainable substitute for conventional Portland cement concrete.

The present study focuses on predicting the behavior of the reinforced concrete (RC) beam–column joints when subjected to seismic loads with the newly proposed concrete damage plasticity (CDP) model for modeling the behavior of concrete. ABAQUS/CAE is used to model the behavior of beam–column joint. Input parameters for the concrete damage plasticity model are adopted from the proposed model. Parametric studies are performed for studying the influence of variation of the dilation angle and eccentricity on the behavior of the beam–column joint when subjected to seismic loads. Ultra High-Performance Fiber Reinforced Concrete (UHPFRC) strip is used for strengthening the beam–column joint against seismic loads. The UHPFRC material is wrapped all along the beam–column joint as a layer for strengthening purposes. Three different thicknesses of UHPFRC strips are used for strengthening the beam–column joint to assess the maximum load-carrying capacity. Results indicated that the proposed CDP model is accurately predicting the behavior of the RC beam–column joint. It is observed that as the thickness of the strip increases, the resistance of the beam–column joint against seismic loads is also increased. It is also observed that the UHPFRC material is more ductile when compared with normal concrete.