Improving mechanical properties and sustainability of high-strength engineered cementitious composites (ECC) using diatomite

Abstract

High-strength engineered cementitious composites (ECC) typically require higher cement content, which is negative from the sustainability point of view. To alleviate this problem, herein a low-cost and eco-friendly high-strength ECC (with a compressive strength of over 100 MPa) was developed, and diatomite was used to replace a small amount of cement. An appropriate amount of diatomite was found to improve the compressive strength, tensile strength and first cracking strength of ECC, but at the expense of part of the strain capacity (still all higher than 2.9%). Furthermore, the high pozzolanic activity and specific surface area of diatomite also increased the autogenous shrinkage, but reduced the drying shrinkage of ECC due to its internal curing effect. The incorporation of diatomite improved the pore structure of ECC, consumed more Ca(OH)2, and enhanced the hydration degree of the mixture. In the end, the economic and environmental benefits of diatomite-modified ECC were also evaluated, and the cost, non-renewable energy demand, and global warming potential of ECC with 3% diatomite were reduced compared to plain ECC by 12.9, 15.1, and 13.3%, respectively. The developed high-strength ECC is therefore a low-cost and eco-friendly alternative to the traditional one.

Investigation on the shrinkage performance of engineered cementitious composite (ECC) constrained by steel ring

“…The experimental result carried out by Yao [14] and Li [15] showed that the pozzolanic reaction of fly ash in ECC plays a significant role in the refinement of pore structure and reduction of restrained shrinkage, presenting an extremely low density of crack under drying condition. Besides of fly ash, the addition of limestone-calcined clay [16] and diatomite [17] are also able to inhibit the shrinkage evolution of ECC. However, the incorporation of ground granulated blast furnace slag (GGBFS) in ECC exhibits earlier cracking time and larger crack width, which indicates that GGBFS has an adverse effect on the cracking resistance of ECC [18] .…”

Investigation on the shrinkage performance of engineered cementitious composite (ECC) constrained by steel ring

“…The experimental result carried out by Yao [14] and Li [15] showed that the pozzolanic reaction of fly ash in ECC plays a significant role in the refinement of pore structure and reduction of restrained shrinkage, presenting an extremely low density of crack under drying condition. Besides of fly ash, the addition of limestone-calcined clay [16] and diatomite [17] are also able to inhibit the shrinkage evolution of ECC. However, the incorporation of ground granulated blast furnace slag (GGBFS) in ECC exhibits earlier cracking time and larger crack width, which indicates that GGBFS has an adverse effect on the cracking resistance of ECC [18] .…”

Torsional strength design method and cost analysis of FRP bars reinforced ECC beams without stirrups

“…The cost of ECC is higher than the traditional concrete and SFRC because of using short fibers and a large amount of cementitious materials. [31][32][33] Fortunately, ECC owns excellent mechanical properties through the bridging effect of fiber, [15][16][17][18][19][20][21][22][23][24][25] which is beneficial for obtaining the ECC structures with excellent mechanical performance. 27,[34][35][36][37][38][39] ECC buildings under the lateral loading show better structural performance than RC buildings, and ECC with high tensile capacity helps to decrease steel reinforcement by 15%.…”

Properties of Cement-Based Materials Incorporating Ground-Recycled Diatom

“…Some studies have supported this hypothesis by thermogravimetric analysis, measuring the decrease in Portlandite content of cement pastes [12,14] and lime pastes [16]. Complementarily, some research works point out the internal curing effect as a contributor to strength development in diatomite blended cements [9,17,18]. The positive effect of diatomite as a supplementary cementitious material is maintained even after heating concrete at temperatures up to 1000 °C; however, only low replacement ratios (< 15%) lead to satisfactory strength results, as the dilution of Portland cement compensates any other positive effects with higher contents [4,15,17,19].…”

Investigation on the shrinkage performance of engineered cementitious composite (ECC) constrained by steel ring

“…The experimental result carried out by Yao [14] and Li [15] showed that the pozzolanic reaction of fly ash in ECC plays a significant role in the refinement of pore structure and reduction of restrained shrinkage, presenting an extremely low density of crack under drying condition. Besides of fly ash, the addition of limestone-calcined clay [16] and diatomite [17] are also able to inhibit the shrinkage evolution of ECC. However, the incorporation of ground granulated blast furnace slag (GGBFS) in ECC exhibits earlier cracking time and larger crack width, which indicates that GGBFS has an adverse effect on the cracking resistance of ECC [18] .…”

Torsional strength design method and cost analysis of FRP bars reinforced ECC beams without stirrups

“…The cost of ECC is higher than the traditional concrete and SFRC because of using short fibers and a large amount of cementitious materials. [31][32][33] Fortunately, ECC owns excellent mechanical properties through the bridging effect of fiber, [15][16][17][18][19][20][21][22][23][24][25] which is beneficial for obtaining the ECC structures with excellent mechanical performance. 27,[34][35][36][37][38][39] ECC buildings under the lateral loading show better structural performance than RC buildings, and ECC with high tensile capacity helps to decrease steel reinforcement by 15%.…”

Properties of Cement-Based Materials Incorporating Ground-Recycled Diatom

“…Some studies have supported this hypothesis by thermogravimetric analysis, measuring the decrease in Portlandite content of cement pastes [12,14] and lime pastes [16]. Complementarily, some research works point out the internal curing effect as a contributor to strength development in diatomite blended cements [9,17,18]. The positive effect of diatomite as a supplementary cementitious material is maintained even after heating concrete at temperatures up to 1000 °C; however, only low replacement ratios (< 15%) lead to satisfactory strength results, as the dilution of Portland cement compensates any other positive effects with higher contents [4,15,17,19].…”

Investigation on the shrinkage performance of engineered cementitious composite (ECC) constrained by steel ring

“…The experimental result carried out by Yao [14] and Li [15] showed that the pozzolanic reaction of fly ash in ECC plays a significant role in the refinement of pore structure and reduction of restrained shrinkage, presenting an extremely low density of crack under drying condition. Besides of fly ash, the addition of limestone-calcined clay [16] and diatomite [17] are also able to inhibit the shrinkage evolution of ECC. However, the incorporation of ground granulated blast furnace slag (GGBFS) in ECC exhibits earlier cracking time and larger crack width, which indicates that GGBFS has an adverse effect on the cracking resistance of ECC [18] .…”

Torsional strength design method and cost analysis of FRP bars reinforced ECC beams without stirrups

“…The cost of ECC is higher than the traditional concrete and SFRC because of using short fibers and a large amount of cementitious materials. [31][32][33] Fortunately, ECC owns excellent mechanical properties through the bridging effect of fiber, [15][16][17][18][19][20][21][22][23][24][25] which is beneficial for obtaining the ECC structures with excellent mechanical performance. 27,[34][35][36][37][38][39] ECC buildings under the lateral loading show better structural performance than RC buildings, and ECC with high tensile capacity helps to decrease steel reinforcement by 15%.…”

Properties of Cement-Based Materials Incorporating Ground-Recycled Diatom

“…Some studies have supported this hypothesis by thermogravimetric analysis, measuring the decrease in Portlandite content of cement pastes [12,14] and lime pastes [16]. Complementarily, some research works point out the internal curing effect as a contributor to strength development in diatomite blended cements [9,17,18]. The positive effect of diatomite as a supplementary cementitious material is maintained even after heating concrete at temperatures up to 1000 °C; however, only low replacement ratios (< 15%) lead to satisfactory strength results, as the dilution of Portland cement compensates any other positive effects with higher contents [4,15,17,19].…”