Load-displacement Relationship Research Articles

Anchorage behavior of grouting sleeves under uniaxial and cyclic loading-A comparative study of the internal structure of sleeves

Grouting sleeves as one of connection methods of splice rebars are used widely in prefabricated construction. The performance of sleeve connection has a significant influence on the seismic performance of prefabricated structure. The internal structure of sleeve is a key factor affecting the bond performance of the sleeves. In this study, a new kind of sleeve was developed, where internal threads and wedges were the main variables studied contrastively. Three specifications of threads and wedges were designed and 10 groups (30 specimens) were tested under uniaxial loading, cyclic loading at high stress and cyclic loading at large strain. The results of failure mode, load-displacement relation, load-strain relation and internal damage phenomenon were analyzed comparatively. The results showed that both threads and wedges can improve the anchoring performance of sleeves, while the specimens with threads exhibit a more ideal stress distribution and a lower damage compared to the ones with wedges. Furthermore, the combination of these two methods showed excellent mechanical properties. The threads size and the wedges slope angle of sleeves influence the stress distribution and damage state of grouting materials greatly. For the rebar with diameter of 12 mm, threads with a height Ht of 1.5 mm and the wedges that dw is 1 mm–2 mm were suggested, and the cost was acceptable.

Load-bearing capacity of wood polyvinyl chloride composite log-walls with openings strengthened with steel flat bars via experimental and numerical studies

In this research, the load bearing behavior of strengthened hollow WPVC composite log-wall panels using steel flat bars (SFBs) was examined experimentally and verified numerically with a finite element model (FE-model). The validated FE-model was extended to study the load carrying behavior of full-scale log-wall panels. The results indicated that the new log element cross-section gave an average maximum load-bearing capacity of 40.3 kN/m at an average maximum displacement of 12.07 mm and prevented side sway and fracture near the connection between the web and the flange. For the strengthened middle part between the openings of the log-wall panel, SFBs and an extra flange member provided an average maximum load-bearing capacity of 48 kN/m at an average maximum displacement of 20.4 mm, and helped to control the deformation shape, prevented the separation of log layers, and provided the panel with low ductility. Good bonding between the contact surfaces of the WPVC composite and the SFBs was achieved. In a comparison between the experiment and the FE-model simulation, similar trends in the load–displacement relationship, strain intensity, and deformed shape were obtained, which confirmed the accuracy of the FE-model used. The numerical results for full-scale log-wall panels using the validated FE-model also showed that WPVC composite panels with two openings can carry loads of 4.12 and 4.69 kN/m, which satisfies the requirements for a load-bearing wall in a one-story house with a roof span of up to 4 m and a total load of less than 3.28 kN/m, excluding the lateral load.

Mechanical Properties and Constitutive Relationship of the High-Durable Parallel Strand Bamboo

Engineered bamboo has recently received lots of attention of civil engineers and professional researchers due to its better mechanical performance than that of softwood timber. Parallel strand bamboo is one important part of engineered bamboo for its excellent durable performance compared to the laminated veneer bamboo. The required curing temperature in hot-pressing process is usually higher than 120°C to reduce the content of nutritional ingredients and hemy cellulose, and to avoid the decay from the environment and insects. Nonetheless, the appearance of engineered bamboo gets darker with the increase of temperature during the hot-pressing process. In order to minimize the color deepening while maintaining the durability, a high-durable parallel strand bamboo (HPSB) with relative high hot-pressing temperature (140°C) was produced and tested. The present study investigates the mechanical performance through tension, compression, shear and bending tests. The experimental behavior of the specimens was identified, including the failure mode and load-displacement relationship. It was demonstrated that the HPSB material had better mechanical performance parallel to grain, making it as a considerable structural material. The average elastic modulus parallel to grain was 14.1 GPa, and the tensile and compressive strengths were 120.7 MPa and 121.0 MPa, respectively. The tension perpendicular to grain should be avoided in the practical application due to the lower strength and elastic modulus. Two stress-strain relationships of tension and compression parallel to grain, including three-linear and quadratic function models, were proposed and compared with the experimental results. The three-linear model was then applied to the finite element model. The finite element analysis using ANSYS software was conducted to validate the feasibility of the constitutive relationship. The quadratic function model showed better agreement with the experimental results, but the three-linear relationship was also precise enough to analyze the bending tests of HPSB material, whereas being less accurate to describe the elastic-plastic compression behavior.

A Review on the Mechanical Behaviour of Bamboo Reinforced Concrete Beams

In light of the increasing demand for sustainable building materials, the effectiveness of bamboo utilization in various fields has become the object of scientists’ close attention. The increased interest in bamboo is explained by its sustainable characteristics, which make it the most preferred material for environmentally friendly and costeffective construction compared to conventional ones. Applicability of bamboo is vast and diverse: from decoration and furniture to structural members and reinforcement. Due to the low price, rich resources, and high elasticity, bamboo culms have also been used as an alternative to steel reinforcement in concrete structures. Extensive research has been done to assess feasibility of bamboo reinforcement in structural elements made of concrete. This article discusses the mechanical properties of three types of structural bamboo reinforced concrete (BRC) beams. Existing original papers on the mechanical behaviour of structural BRC members were studied, and the fundamental properties including typical failure modes, reasons of failure, load-displacement relationships, and influencing factors were discussed and described. Observations and conclusions of the review will contribute to deep understanding of structural feasibility of BRC beams and serve as a base for future research.

Cyclic performance of emulative precast beam to column con-nection with corbel using dowel bar

The objective of this study is to examine the seismic performance of exterior and interior types of an emulative precast beam to column connection, constructed with grouted steel dowel bar and cast-in-situ concrete under quasi-static reversed cyclic loading. The dowel bar connection between the precast structural elements is achieved by inserting the dowel bar into the column corbel's holes and the precast portion of the beam. To secure the dowel bar's anchorage, these holes are packed with non-shrinkage grout and then cast-in-situ concreting is done in the joint core and the entire upper segment of the precast beam. In the past, particularly after an earthquake in the Emilia-Romagna region of Italy in May 2012 (Ercolino, Magliulo, & Manfredi, 2016), witnessed damage to precast reinforced concrete structures was more likely to occur in the precast beam-column joint section. Hence, it’s essential to improve the performance of the beam-column joint to withstand all possible lateral load combinations, which are to be included in the design and detailing of the precast structural components. This study analyzed an eight-story RC frame building for earthquake loading using Staad.Pro software. The exterior and interior types of proposed beam-column connections were designed and detailed using the design forces and moments computed by the Staad.Pro analysis, in accordance with the Indian standard codes (IS 456, 2000), (IS 1893, 2016)and (IS 13920, 2016). The beam-column joint behavior under quasi-static cyclic loading was studied using one-third scaled-down test specimens, i.e., monolithic (MBC-EJ & MBC-IJ) and emulative beam-column (EBC-EJ & EBC-IJ) exterior and interior joints. In that proposed emulative connection, the structural continuity and compatibility between the precast elements were achieved through the corbel with the dowel bar and cast-in-situ concreting. The test specimen’s ultimate and yield load carrying capacity, energy dissipation capacity, stiffness degradation, and ductility parameters were determined based on the obtained load-displacement hysteresis relationship. Based on the findings, the precast exterior joint specimens (EBC-EJ) were found to be 14.36% more ductile and 13.23% more energy dissipative than monolithic exterior joint specimens (MBC-EJ). Similarly, precast interior joint specimens (EBC-IJ) outperformed monolithic interior joint specimens (MBC-IJ) by 6.27% more ductility and 16.86% more energy dissipation. Therefore, the experimental results confirmed that using grouted dowel bars and wet concreting in the joint area enhances rigidity and structural continuity, as well as improves the ultimate strength of precast connections to a level that closely resembles typical monolithic beam-column joints.

Strut-and-tie and finite element modelling of unsymmetrically-loaded deep beams

A strut-and-tie model (STM) for unsymmetrically-loaded deep beams is proposed in this paper through simplifying the unsymmetrical problem into symmetrical and anti-symmetrical problems. This analytical solution starts with derivations of principal compressive stress fields based on the theory of elasticity. Furthermore, a minimum-strain-energy criterion is adopted to define the optimal STM geometry from the stress field, including the dimensions of struts and nodal zones, and strut angles. The proposed STM is validated against 140 test results, including 14 unsymmetrically-loaded deep beams and 126 symmetric deep and short beams, and finite element models (FEMs) for the 14 unsymmetrical deep beams. The FEM is also used to simulate the load-displacement relationships of unsymmetrical deep beams that could not be modelled by STM. In addition, a worked example is presented to demonstrate in detail the procedure of analysing an unsymmetrically-loaded deep beam using the proposed solution. In summary, the STM predictions are in good agreement with experimental results and FEM predictions. Therefore, the proposed STM is capable of giving accurate and consistent predictions for both symmetrical and unsymmetrical deep and short beams.

Experimental and numerical investigation on progressive collapse resistance of RC frame structures considering transverse beam and slab effects

In order to investigate the load carrying mechanisms in resisting progressive collapse for reinforced concrete (RC) structures while considering transverse beam and slab effects, a series of four 1/4-scale RC substructural specimens were tested and the failure modes, load-displacement relationships, and load redistribution responses are presented in this paper. Two beam-column subassemblies were tested as control specimens. The third specimen was a cross-beam subassembly composed of a transverse beam and a longitudinal beam which had the same reinforcement detailing as the control specimens to investigate the transverse beam effects excluding RC slab. The last specimen had identical beams with the third specimen, but including an RC slab to consider the slab effects, which could be used to simulate the mechanism to resist progressive collapse developed in a practical frame structure. Test results showed that the load-carrying capacity of a cross-beam system at the compressive arch stage was almost equal to the sum of the load-carrying capacities of these two crossed beams, whereas the transverse beam and slab effects could increase the capacity of a two-span beam by as much as 340%. Thus, transverse beam and slab effects should not be ignored in the simulation of progressive collapse for RC frame structures. Based on the simplified models calculating nonlinear static load-deflection responses for RC two-span beams proposed in the previous study and load-displacement relationships obtained in this test, computational models calculating load-deflection responses for cross-beam subassembly excluding or including slab were established and verified.

An Explicit Finite-Element Modeling Method for Masonry Walls Using Continuum Shell Element

This paper presents an explicit finite-element (FE) model formulated using the continuum shell element to examine the behavior of unreinforced and externally strengthened masonry walls. Masonry is modeled as a homogenized material capable of producing elastic and inelastic behavior with distinct directional properties. The macroscopic properties of masonry are defined using a Hill-type and a Rankine-type yield surface to model its behavior under compression and tension, respectively, which are embedded in a VUMAT user material subroutine developed using the ABAQUS Explicit algorithm. Alongside the mechanical properties of masonry, the thickness direction properties of the continuum shell element are defined through the input file to ensure compatibility between the algorithm used in the VUMAT and the continuum shell formulation. The parameters of the FE model have been validated with the test data sets of a total of six out-of-plane and in-plane loaded masonry walls taken from three separate experimental programs reported in the literature. A close match between the experimental and FE model failure mode and load–displacement relation was observed. The model is extended to predict the behavior of externally strengthened walls, which experienced the debonding of the carbon fiber-reinforced polymer (CFRP) layers from the masonry substrate. A significant increase in the in-plane capacity of the strengthened walls was observed.

Lateral performances of traditional wooden frame with loose penetrated mortise-tenon connection and column foot models

Traditional wooden structures in China have free-standing columns on top of stone bases and the beams and columns connected by mortise-tenon joints. Many of them have been in service for hundreds of years withstanding many seismic events, and yet their performances against lateral loadings are not clear. This paper studies the behavior of a wooden portal frame with penetrated mortise-tenon (PMT) connections and column foot (CF) connections under transverse load. An analytical model for a planar loose PMT connection is proposed based on the load-displacement relationship. The mechanical behavior of these loose connections with the friction-slip-contact mechanism is studied with clear evidences of negative stiffness in the lateral resistance of the wooden frame. The different contact states of the PMT and CF connections in the load resisting process are studied. Results indicate that the lateral performances of the wooden frame are dependent on the synergistic action of the PMT and CF connections. The lateral deflection mechanism of a wooden frame is strongly affected by the loose PMT connections and the P-Δ effect of the supporting columns.

Numerical investigation of concrete filled hollow precast composite columns subjected to lateral cyclic loading

This paper describes a numerical study performed to investigate the behaviour of concrete infilled hollow precast composite columns (HPCC) subjected to lateral cyclic loading. Finite element analysis of monolithic (RC) and composite (HPCC1 and HPCC2) columns are performed and the results thus obtained are compared with documented experimental results. The present study focuses on the capability of numerical codes to capture the behaviour of the columns, such as load–displacement relationship, softening and failure modes under cyclic loading. To capture the performance of tested composite columns, a study was first performed to select a suitable material model that can further be considered appropriate to depict the cyclic performance of reinforced concrete (RC) structures. Moreover, the investigation was performed to model two concrete surfaces (precast and cast-in-situ) in contact through a contact algorithm for a precast encased composite column. Finally, a study on interface shear stress transfer mechanism and effects of confinement provided by the encasement to the inner core was performed for HPCC1 and HPCC2 composite columns. After performing numerical study and comparing with the obtained test results, a continuous surface cap material model (MAT 159) available in LS-DYNA FE code was observed to be suitable to model concrete for analyzing the behavior of RC structures subjected to lateral cyclic loading. Moreover, to simulate the behaviour of composite structures, the use of a tiebreak contact algorithm is suggested. It was observed that due to the presence of cross-ties penetrating into the inner core of HPCC1, the composite action between the inner core and outer precast encasement was enhanced, with delayed damage in the outer encasement. However, in composite column HPCC2, the ties did not penetrate into the inner column core, so interface shear strength, resulted only from cohesion and friction, caused severe damage in the outer encasement at ultimate load. The presence of a single tie and smaller thickness of precast encasement in HPCC1 resulted in lower displacement ductility of HPCC1 compared to composite column HPCC2. Moreover, parametric studies were performed to elucidate the influence of the thickness of the precast plate and reinforcement arrangement to enhance the ductility of the composite columns through a series of numerical analyses of the modified columns.

Experimental investigation on the flexural behavior of laminated bamboo-timber I-beams

I-beams are widely used in construction structures because of their excellent mechanical properties. This research experimentally investigated the flexural performance of composite I-beams made of timber and bamboo to enhance the structural performance of I-beams. A total of six groups of laminated bamboo-timber I-beams with 12 specimens were tested. The laminate materials included bamboo scrimber and Douglas fir. The test parameters included the number and position of the bamboo laminates. Four-point bending experiments were employed to study the failure modes, flexural performance, load-displacement relationships, and strain curves of the bamboo-timber I-beams. The results indicated that the bamboo-timber I-beams mainly showed three failure modes: lower flange tensile failure, web shear failure, and web horizontal penetration crack failure. The load-displacement curves and load-strain curves of all specimens were linear. The deformation capacity of the bamboo-timber beams was significantly improved compared with that of the control timber beams. As the number of layers of the bamboo scrimber increased, the flexural stiffness of the bamboo-timber beams also increased. However, the ultimate bearing capacity of the I-beams was not directly proportional to the number of layers of bamboo scrimber. The bearing capacity and stiffness of the bamboo-timber beams increased by 44.8% and 23.4% on average compared with the control timber beams.

Finite element modeling of tessellated beams

Tessellated Structural-Architectural (TeSA) systems are composed of repeated tiles that can interconnect, be designed to have load carrying capacity, and are aesthetically pleasing. TeSA systems may localize damage to few tiles when subjected to extreme loads, may facilitate easier or faster reparability, and contribute to resilience. This research investigates numerical modeling of simply supported TeSA beams. Finite Element (FE) analysis was performed and the results were validated using experiments of TeSA beams made of Medium Density Fiberboard (MDF). The FE analysis incorporated gaps and interaction between tiles. The results showed that contact properties and gap size between tiles affected the calculated load-displacement relationship and strain of the TeSA beam. Contact properties were captured by a pressure-overclosure relationship, which required calibration using the global load-displacement response obtained from testing. Incorporation of geometric nonlinearity did not affect the results significantly. Beams with varying friction coefficient between tiles, load and support bearing width, Poisson's ratio and aspect ratios were analyzed. The results showed that TeSA beams had smaller stiffness than solid beams with similar dimensions. The outcomes of this research provide insights on the behavior and modeling of TeSA structures.

Progressive collapse resistance of multistory RC frame strengthened with HPFL-BSP

The field of progressive collapse has attracted considerable attention worldwide, while little existing building structure has been constructed with progressive collapse design. Therefore, some researchers began to explore effective strengthening methods to improve the progressive collapse resistance of existing building structures while saving cost, resources, and time. In this paper, two 1-bay-by-2-bay two-story reinforced concrete (RC) frames with the loss of one edge column were constructed and tested, including the control and strengthened specimens. The strengthened specimen was strengthened with high-performance ferrocement laminate and bonded steel plates to investigate the strengthening effectiveness. Based on the data collected during the experiment and simulated results, crack development patterns, load-displacement relations, lateral deformation , load distribution, and the effect of strengthening were discussed. Additionally, the finite-element (FE) simulation and the theoretical analysis for such structure were implemented. The results show that the initial stiffness and bearing capacity of frame increased after strengthening. Increasing the steel strand quantity, the peak load can be significantly increased. The stiffness in different floor will have an effect on the load bearing distribution. Higher stiffness in floor will bear much vertical load. The axial compression on adjacent columns increased while decreased in the diagonal columns. The contribution to bearing capacity of slab is weaker than beams. The slab could share about 2/3 vertical load of beams for control specimens and less than 1/2 vertical load of beams for strengthening specimens.

Enhance the energy dissipation ability of sleeve-type negative stiffness structures via a phase-difference mechanism

Sleeve-type negative stiffness structures (ST-NSSs) can dissipate harmful mechanical energy in a reusable and controllable approach, and they are lightweight and with high mechanical performance, thus have a wide range of application prospects in many engineering fields. However, the load-displacement curve of existing ST-NSSs exhibits a waved shape, which has limited their energy dissipation ability (The ideal energy dissipation structure is required to have a stable and controllable load response). In this work, a new strategy is proposed by combing multiple ST-NSS cells in parallel with a phase-differences mechanism to improve the energy dissipation ability. A theoretical model is created to predict the load-displacement relationship of the parallel structure; a program is developed to obtain the numerical solution of the problem, and these two approaches are verified by quasi-static loading-unloading experiments. The results show that the proposed strategy can significantly improve the energy dissipation ability of parallel structures using a small number of negative stiffness cells. Additionally, it is found that by limiting the displacement range, the energy dissipation ability of the parallel structure can be further improved. This study brings a new way to design reusable, programable, high-performance, and highly adaptable negative stiffness structures for dissipating harmful mechanical energy in impacting and vibration.

Nonlinear Finite-Element Analysis of the Seismic Behavior of RC Column–Steel Beam Connections with Shear Failure Mode

RC column–steel beam (RCS) systems, a novel type of hybrid structure, have been used widely in recent decades owing to their excellent seismic performance and simple fabrication process. However, due to the effects of variable strengthening configurations on force-transfer mechanisms, the mechanical behavior of RCS connections has not been fully understood by existing experimental studies. This paper proposes a reliable finite-element model of RCS connections and investigated the effects of different strengthening configurations and design parameters on the seismic performance and shear mechanism. A detailed three-dimensional finite-element model was developed and validated against previously obtained experimental results, including load–displacement relationships and cracking patterns. Parametric studies based on the validated model were conducted. The studies showed that the axial load ratio significantly affects the failure mode and ductility of the connection. The load-carrying capacity of the connection is enhanced significantly when the concrete strength is increased. Furthermore, additional yield capacity of steel plates and transverse reinforcements has limited effects on crack propagation and strain state when adequate resistance can be provided.

Pre- and post-punching performances of eccentrically loaded slab-column joints with in-plane restraints

In flat plate structures, interior slab-column joints are subjected to in-plane restraints and bending-shear actions, which can significantly impact their mechanical performance to resist progressive collapse. However, research in this area is still lacking. This paper presents experimental and numerical studies of pre- and post-punching performances of eccentrically loaded slab-column joints with in-plane restraints. Quasi-static tests were conducted on seven joint specimens, including one concentrically loaded (CL) joint and six eccentrically loaded (EL) ones. The effects of critical structural parameters (i.e., eccentricity, slab thickness and reinforcement ratio) on the pre- and post-punching performances were investigated by analysing the load–displacement relationships, failure modes and material strains. The experimental results indicated that larger eccentricity could lead to more reduction of the peak punching shear capacity by as much as 62%, whereas it has little effect on the post-punching capacity. In addition, the strain results of the through-column rebars showed that, with the well-restrained boundary conditions, the slab flexural reinforcement (FR) was found to resist the applied load to a large extent at small deformations and still able to contribute greatly during the post-punching stage. Numerical analysis was conducted to gain an in-depth understanding toward the effects of varied levels of in-plane restraints on both slab-column joints and actual flat plate structures. It was found that the lateral stiffnesses in the CL joint model with boundary beams and the substructure model were similar, which was around 400 N/mm. Finally, the interactions between the unbalanced moment and shear force were explored and compared with code predictions (ACI318-19 and EC2-04). Without considering the enhancement effects from in-plane restraints, the codes produced over-conservative predictions. Based on the FE analyses, the correlation between the dimensionless ratio e/d (eccentricity/effective thickness of slab) and punching shear strength was simplified by a combined straight line and a power curve.

Cyclic shear displacement model for reinforced concrete columns

Lateral response of reinforced concrete (RC) columns can be modeled and simulated considering three displacement components: flexural displacement, displacement due to slippage of longitudinal bars at column ends, and shear displacement. The incorporation of shear displacement in a computational model is essential for accurate calculation of lateral load–displacement relationship. The contribution of shear displacement can be significant for RC columns with low displacement capacity or ductility. An easy-to-apply shear displacement model is proposed in this study, and implemented in the open source software, OpenSees. The proposed model is based on a pre-defined envelope or monotonic model and does not require updating of modeling parameters during each cycle. The model is validated using experimental data. New rules are developed for the cyclic model to capture the effects of cracking and change in stiffness and strength during the loading and unloading cycles. Comparison of the calculated and measured shear displacements indicates that the cyclic shear response can be captured by the proposed model.

Theoretical and numerical investigation of mode‐I delamination of composite double‐cantilever beam with partially reinforced arms

AbstractIn this paper, a theoretical analysis model and two simulation methods are applied to characterize the quasi‐static and fatigue delamination of composite double‐cantilever beam (DCB) with partially reinforced arms. The test data of partially reinforced DCB were used as benchmark to verify the analysis model and simulation, and cohesive zone models (CZMs) and virtual crack closure technique (VCCT) are used in simulation. It is shown that the partially reinforced DCB has a unique double‐peak load–displacement relationship, rising and sudden release of R‐curve near the reinforced area, and produces instability development. By comparing the results of simulation and experiment, the simulation based on the exponential CZM can calculate the delamination of partially reinforced DCB under both quasi‐static and fatigue loading, while VCCT method will generate a straight delamination front edge under the reinforced area and underestimates the influence of the previous load on the later due to the lost of microdamage from previous loading.

Research on fracture parameters of asphalt mixture based on XFEM and J Integral method

The fracture toughness and load displacement relationship of the three point bending (3pb) asphalt mixture specimens with different notch position were experimentally and numerical investigated. Firstly, the extended finite element was used to simulate the three-point bending and fracture process of asphalt mixture beam, and the load and displacement curves were obtained, which were compared with the test results to verify the accuracy of the XFEM model. Secondly, J contour integral method in ABAQUS software was used to solve the stress intensity factor under the three-point bending of asphalt mixture, and the fracture parameters of asphalt mixture were provided by the numerical calculation results. The results showed that the offset distance increases, the influence of the type II crack in the fracture process increases, but the type I crack still was dominant.

Crack evolution in the Brazilian disks of the mine tailings-based geopolymers measured from digital image correlations: An experimental investigation considering the effects of class F fly ash additions

Mine tailings-based geopolymer was proved to be successfully created with enhanced strength for potentially construction and building materials applications. Through geopolymerization, the mining wastes can be reused and the storage, economic, and environmental issues can be mitigated. However, the geopolymerization effect was relatively limited comparing to the ordinary Portland concrete. Therefore, the additions of amorphous supplementary fly ash were considered in the paper. In this study, class F fly ash was utilized as an amorphous additive and the additional aluminum source to adjust the Si: Al ratio for better geopolymerization effects. To better understand the mechanical and fracture behavior of the geopolymer after adding fly ash, the Brazilian indirect tensile tests were then conducted to evaluate the influence of different fly ash additions, 5%, 10%, 15%, and 20%, on the tensile strength of the geopolymer. Meanwhile, besides the load-displacement relationships, the digital image correlation was used to investigate the crack initiation and propagation in the geopolymer disks with respect to different fly ash additions. The crack evolution was evaluated from the full-field strain field from digital image correlation. Crack opening displacements, failure patterns, and strain evolutions for the geopolymer disks with different fly ash additions were examined. Results showed that, under the presented sample curing condition, the geopolymer with 15% fly ash addition had the largest tensile strength. Geopolymer disks without and with lower fly ash additions had plastic deformation prior to the peak load that can obviously be classified into three different stages. The geopolymer made without and with lower fly ash additions had both tensile and shear crack modes.