Issue 43

S. Jing et alii, Frattura ed Integrità Strutturale, 43 (2018) 33-42; DOI: 10.3221/IGF-ESIS.43.02 37 of cement, which may cause a negative influence on the density and strength of the materials in the early stage of hydration [13]. 3) The addition of superplasticizer can disperse and lubricate the cement, which reduces the water consumption and makes the uniformity of the mixture better. However, if the plasticizer content is too large, it may extend the setting time of the high toughness cementitious composite and reduce its initial strength. In this experiment, the compressive strength first increases and then decreases with the mass ratio of superplasticizer to cementing material changing from 0.4% to 1.0%, indicating there is an optimum dosage of superplasticizer. 4) Experimental data indicate that the compressive strength increases by 0.6% and 3.0% with the sand-binder ratio changing from 0.30 to 0.33 and 0.36. According to the result of the range analysis, the impact of sand-binder on the compressive strength of the material is minimal. Figure 1 : Failure mode of test specimens. Figure 2 : Influence of Changes in Factors on Compressive Strength. U NIAXIAL TENSILE EXPERIMENT iterature [14] found through a large number of experiments that cracks could be extended to steady-state cracking mode during the tensile experiment of the high toughness cementitious composite. The tensile stress instantly dropped when the first crack appeared and then immediately returned, then new cracks were created as the load increased without increasing the crack width. Jun Zhang et al. [15] carried out the tensile experiment with ECC prism specimens using six different mixing ratios. The tensile stress-strain curve was measured and the ultimate tensile strain was found to be 1.7%. Shilang Xu [16] used thin plate specimens of ECC to carry out the tensile experiment. The result showed that ECC had a significant quasi-strain hardening property and the crack width could be effectively controlled within 100 μm. Figure 3 : The thin Plate Specimen for uniaxial compression experiment. Figure 4 : Experimental set-up for niaxial tensile test. L