scholarly journals Multi-Objective Optimization of Nano-Silica Modified Cement-Based Materials Mixed With Supplementary Cementitious Materials Based on Response Surface Method

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiuzhi Zhang ◽  
Liming Lin ◽  
Mengdi Bi ◽  
Hailong Sun ◽  
Heng Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Response Surface ◽  
Cementitious Materials ◽  
Plastic Viscosity ◽  
Supplementary Cementitious Materials ◽  
Quadratic Term ◽  
Multi Objective Optimization ◽  
Nano Silica ◽  
Surface Method ◽  
Cement Based Materials

This paper investigates the effect of supplementary cementitious materials (SCMs) on the fresh and mechanical properties of nano-silica modified cement-based materials (NSMCBM) based on the response surface method (RSM). Fly ash (FA), ground granulated blast-furnace slag (GGBFS), and silica fume (SF) were selected and the Box-Behnken design (BBD) method was used to design mix proportion. Besides, the quadratic term model was used to describe the relationship between independent variables and responses including fluidity, yield stress, plastic viscosity, thixotropy, and 3, 7, 28, and 56 d compressive strength. Based on the quadratic term model, the response surface of each response was drawn to understand the influence of SCMs. Results showed that FA had significant effect on fluidity and thixotropy while three kinds of SCMs had extremely significant effect on plastic viscosity. Response surface plot showed that NS could increase the plastic viscosity of NSMCBM to 1.445 Pa•s (M16). However, the addition of FA and GGBFS decreased the plastic viscosity to 0.9 Pa•s, which was comparable with the reference sample (M17). Such value was 37.7% lower than that of M16. Meanwhile, NS complemented the reduction of compressive strength caused by SCMs. Thus, the synergy effect of SCMs and NS could improve both fresh and mechanical properties. At last, multi-objective optimization was utilized to optimize the proportion of SCMs considering the interaction between SCMs to achieve desirable parameters.

Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

2021 ◽  
Vol 1036 ◽  
pp. 240-246
Author(s):  
Jin Tang ◽  
Su Hua Ma ◽  
Wei Feng Li ◽  
Hui Yang ◽  
Xiao Dong Shen
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Research Progress ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Early Hydration ◽  
Calcined Clay ◽  
Dense Microstructure

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

Enhanced mechanical properties of wood ash and fly ash as supplementary cementitious materials

2017 ◽  
Vol 116 (7) ◽  
pp. 355-361 ◽  
Author(s):  
Zaib Hussain ◽  
Rohama Maqsood ◽  
Muhammad Imran Din ◽  
Shahzad Maqsood Khan ◽  
Akhtar Shahnaz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Cementitious Materials ◽  
Wood Ash ◽  
Supplementary Cementitious Materials
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