Quantitative Evaluation of Crack Resistance Mechanism of Blast Furnace Slag Blended Cement Concrete via Restrained Shrinkage Stress Analysis

Abstract

Application of blast-furnace slag blended cement is an important option to reduce carbon dioxide emission peculiar to concrete materials in construction, and concrete structures using the blended cement concrete (hereafter denoted as BFS concrete) is in great demand. However, shrinkage cracking resistance of BFS concrete decreases at high temperatures. In this study, mechanisms of the reduction of cracking resistance at high temperatures were investigated aiming at the control of shrinkage cracking of BFS concrete as the final goal. Constitutive material properties necessary for restrained shrinkage stress analysis were derived through experiments including such as restrained cracking test under a temperature of 30, 20 and 10°C, free shrinkage test, and compressive creep test. On the basis of the constitutive material properties obtained with the above tests, applicability of existing restrained shrinkage stress analysis to BSF concrete was examined. Analytical results indicate that the stress analysis was found to reproduce the cracking behavior at an ambient temperature from 10 to 20°C. However, at an ambient temperature of 30°C, the analysis overestimates restrained shrinkage stress, which is considered due to underestimating creep effects. This underestimation may occur due to surface micro-cracks eminently generated on surface.

Effect of Type of Cement and Expansive Agent on the Hardening of Steam-Cured Concrete

“…In addition, it is apparent from previous studies that SCC imparts high durability and quality to structures [2][3][4]. However, concrete generally has a large self-shrinkage because of its low water-binder ratio and a large amount of powder [5][6][7][8][9][10]. An expansive agent may be added to introduce chemical pre-stress to ensure an external pressure in pre-cast concrete products such as Hume pipes and box culverts [11].…”

Impacts of Trace Additives and Early-Stage Curing Conditions on the Shrinkage Cracking Resistance of Blast-Furnace Slag Cement Concrete

“…Because importance of early-stage wet curing was emphasized in a literature (Aly and Sanjayan 2008), effects of wet curing, in addition to types of binder, on cracking resistance were studied. Combining these parameters and respective levels, four mix proportions of BLS were determined as shown in Table 2, where another six mixes including BB and OPC concretes, as reported elsewhere (Kanda et al 2015b), were also referred to for comparison.…”