Influence of local raw materials on the mechanical behaviour and fracture process of PVA-SHCC

Abstract

This paper addresses the results of an investigation on the influence of the Brazilian raw materials on the mechanical performance of Strain Hardening Cementitious Composites (SHCC). The mixtures were produced with variations of fly ash/cement and sand/cement proportions and with different maximum sand particle. Mechanical properties were evaluated by direct tension, bending and compression tests. Crack formation under direct tension and bending loads was also investigated. The results indicate that the use of high quantities of fly ash with low quantities of fine sand is the ideal combination to obtain strain hardening composites with tensile strain capacity superior to 3% using local materials. The increase in the sand content and particle size affects the behavior of the composites and tended to reduce the strain capacity of the specimens by up to 30%. Keeping constant the fly ash/cement and sand/cement rates it was found that the crack density and width measured under direct tension are only affected by the diameter of the sand for tensile strains in the range of 2%. The same general trends were observed for specimens submitted to compressive and bending loads.

Comparative testing of crack formation in strain-hardening cement-based composites (SHCC)

“…Clearly different procedures were followed, and the test ages range from 14 to 28 days. Details of the respective curing conditions and characterising test methods are described in detail in [7] for L3, [2] for L4 and in [3] for L5.…”

“…It is clear that a significant range of specimen gauge area cross-section size (30 mm 9 13 mm up to 60 mm 9 30 mm) was used, and lengths ranging from 80 mm to 120 mm. For more detail on the test setup, the reader is referred to [14,13] for L1, [15] for L2, [7] for L3, [2] for L4 and [3] for L5.…”

Numerical Simulation on the Tensile Strain Hardening Behaviour of Engineered Cementitious Composites (Ecc)

“…The performance of the adopted calibration approach described in preceding section for simulating tensile strain hardening behaviour are further validated with more experimental results. The works by Choi et al [27], Magalhaes et al [28], Li et al [29], Ding et al [30], Lu et al [31] and Nematollahi et al [32] are chosen for the verification. All specimens chosen to have tensile properties enhanced by PVA fibres and with dogbone-shaped size and geometry based on JSCE standard [24], see Figure 4.…”

“…Magalhaes et al [28], Li et al [29] and Ding et al [30] studied the strain hardening behaviour of ECC. Their mix proportions are almost identical where combined mixture of cement and fly ash are used as binder.…”