Development of engineered cementitious composites with limestone powder and blast furnace slag

Abstract

Nowadays limestone powder and blast furnace slag (BFS) are widely used in concrete as blended materials in cement. The replacement of Portland cement by limestone powder and BFS can lower the cost and enhance the greenness of concrete, since the production of these two materials needs less energy and causes less CO 2 emission than Portland cement. Moreover, the use of limestone powder and BFS improves the properties of fresh and hardened concrete, such as workability and durability. Engineered cementitious composites (ECC) is a class of ultra ductile fiber reinforced cementitious composites, characterized by high ductility, tight crack width control and relatively low fiber content. The limestone powder and BFS are used to produce ECC in this research. The mix proportion is designed experimentally by adjusting the amount of limestone powder and BFS, accompanied by four-point bending test and uniaxial tensile test. This study results in an ECC mix proportion with the Portland cement content as low as 15% of powder by weight. This mixture, at 28 days, exhibits a high tensile strain capacity of 3.3%, a tight crack width of 57 lm and a moderate compressive strength of 38 MPa. In order to promote a wide use of ECC, it was tried to simplify the mixing of ECC with only two matrix materials, i.e. BFS cement and limestone powder, instead of three matrix materials. By replacing Portland cement and BFS in the aforementioned ECC mixture with BFS cement, the ECC with BFS cement and limestone powder exhibits a tensile strain capacity of 3.1%, a crack width of 76 lm and a compressive strength of 40 MPa after 28 days of curing.

Development of ductile cementitious composites incorporating microencapsulated phase change materials

“…Newly developed SHCC mixtures were Microencapsulated PCMs used in this study have a mean particle size of 17 lm, which is smaller than the mean particle size of the limestone powder used (26 lm). Therefore, the workabiliy of the mixture is affected when limestone is replaced by PCMs, so the amount of superplasticizer was increased for all mixtures compared to the original mixture developed by Zhou et al [10] (by approx. a factor of four).…”

“…An SHCC mixture developed by Zhou et al [10], named M6, was used. Apart from ordinary Portland cement (OPC), this mixture contains blastfurnace slag and limestone powder as a filler.…”

“…metal like behaviour) due to their multiple cracking ability and a distribution of fine cracks. This is achieved by micromechanical design [9] and addition of a small volume of fine fibres (around 2% per volume), mostly PVA fibres [7,10]. These composites can sustain large strains (up to 5%) which is achieved through formation of a large number of very fine cracks (typically 30-80 lm).…”

Effect of Sustained Flexural Loading on Self-Healing of Engineered Cementitious Composites

“…To account for crack closure on unloading, all crack width measurements were generally made in the unloaded state, and the self-healing capacity under different environments was also typically assessed in the unloaded state. Since the crack width of ECC specimens under sustained flexural load (close to or larger than 100 μm) is found to be almost double that of the unloaded specimen Zhou et al 2010), it is important to examine the self-healing behavior of precracked ECC specimens under sustained flexural loading, which is of great importance for critical assessment of the performance of ECC under comprehensive conditions.…”

Structural Performance of Polymer Fiber Reinforced Engineered Cementitious Composites Subjected to Static and Fatigue Flexural Loading

“…In the past few decades, substitution of SCMs, such as FA and SL, has been of great interest and gradually applied to practical applications of ECC [16][17][18][19][20]. FA is a by-product of the coal power plant, whereas SL is a by-product in the manufacture of pig iron.…”