# Mechanical Properties of Desert Sand-Based Fiber Reinforced Concrete (DS-FRC)
## 2 Experimental Program
### Test Setup and Loading Procedure
#### 2.2.2 Uniaxial Tensile and Compression Test  
The uniaxial tensile test is the most direct method to evaluate the tensile ductility and strain hardening properties of cementitious composites. It has been extensively used in evaluating the tensile properties of high ductility cementitious composites, although there are no uniform codes. Currently, there are many practical tensile test methods in the world, such as in the United States and Japan [48; 49; 51]. In this experiment, the uniaxial tensile and compression tests were in accordance with Japan Society of Civil Engineers (JSCE) [48] and American Society for Testing Materials (ASTM ) C39 [52].  
Twelve specimens were made, including six dumbbell-type specimens for the tension stress-strain curves of DS-FRC and six cylinders, in which three cylinders were used for obtaining uniaxial compression strengths and stress-strain curves and other cylinders for Elastic Modulus and Poisson's ratio. The uniaxial tensile and compression test were conducted on the electronic universal testing machine with the capacity of 1000 kN. The tensile/compression specimens were loaded under the displacement control with constant rates of 0.5 mm/min and 1.0 mm/min, respectively. The stress was measured by the data logging system from machine. Two extensometers were attached to the mid-heights of tensile specimens symmetrically to measure elongation over a gauge of 50 mm, while compression strains were detected by two linear variable differential transformers (LVDT) attached to the mid-heights of specimens. When the deformation of specimens increasingly increased after ultimate compression stresses, the disturbances at the contact points of LVDT were obvious, which lead to the strain readings dispersed and erratic. In this study, exploring the effect of factors on the mechanical properties of DS-FRC was main purpose and the system data can also meet the requirements. Therefore, the load-displacement curves obtained from machine systems were used to calculate the stress-strain relations under the uniaxial compression test. Through keeping the slope of elastic deformation stage consistent, the initial concave phenomenon of compression stress-strain curves caused by the poor contact between the loading surface and the specimen has been adjusted. All compression specimens' ends were capped with sulfur compound to meet the planeness requirements and reduce errors. The test was stopped when load decreased to 20-30% of the ultimate load. The schematics of test devices and methods under uniaxial tensile and compression tests are illustrated in Figure 2a-c.  
The tests of Elastic Modulus and Poisson's ratio were in accordance with JGJ /T70-2009 [50]. It was conducted on the electronic universal testing machine with the capacity of 300 kN and the rate of 1200 N/s. Four strain gauges were symmetrically centered approximately at the mid-height of the cylinders to measure longitudinal strains and transverse deformations respectively. Before formal loading, three cycles of pre-loading were performed up to the 40% of the ultimate compression stress. Then specimens were unloaded and the formal loading was carried out with the same rate. The average value of three tests were used to evaluate the mechanical parameters of DS-FRC in all tests.