مقاله انگلیسی رایگان در مورد تأثیر نسبت آب به سیمان و زمان خیساندن پودر شیشه ضایعاتی بر رفتار بتن سبز – الزویر 2021

Abstract

Keywords

1. Introduction

2. Experimental design

3. Results and discussion

4. Conclusion

5. Data availability

Declaration of Competing Interest

Acknowledgments

References

Abstract

Sustainability in the construction is becoming a major challanges due to the depletion of natural resources and the avialibility of landfill capacity. Additionally, there is an urgent need to improve the properties of concrete and produce environmentally friendly green concrete. From these points, the effect of varying the water-to-cement (w/c) ratios and the soaking time of glass powder (GP) on the activation of the pozzolanic reactivity and the mechanical properties of green concrete were examined. Two w/c ratios (0.6 and 0.7), two glass contents (5% and 30%), and six GP soaking times werer used in this study. The new mixing method (NMM) was used, in which the GP is partially dissolved in water and more Na+ ions than Ca+2 are formed in solution since Na+ ions have higher mobility than Ca2+ ions. The results indicate that greater normalized compressive strength (CS) is achieved under a w/c ratio of 0.7 for 5% and 30% GP content with soaking time of 6 h. This increase is correlated with the formation of more nucleation sites due to the growth of calcium silicate hydrate rather than portlandite. The relative activation index calculation showed that the 30% GP mixes have higher values than 5% GP mixes.

1. Introduction

Sustinable use of natural resources and effective waste utilization in green concrete is becoming increasingly necessary as natural resources become more limited. Further, the exponentially demand of individual habitaion has led to increased demand for new construction. Fabricating new bottles, flasks, or other tools from glass waste is infeasible due to the amount of energy required (collection, transportation and melting). Therefore, researchers have aimed to reuse crushed waste glass or glass powder (GP) as an aggregate in concrete or as a replacement for cement. The amorphous structure and chemical composition of GP and some types of ash are similar to those of cement, and thus induce a similar pozzolanic effect in concrete. The pozzolanic reaction involves the consumption of the weaker portlandite (CH) to produce calcium silicate hydrate (C-S-H), which has a higher CS and density [1–4].

The traditional or conventional mixing method (TMM), in which GP and water are directly mixed into the concrete mixture, has been used extensively to investigate the effect of using GP in concrete [5]. In the new mixing method (NMM), the GP is presoaked in water to partially dissolve it before it is mixed into the concrete mixture, thus activating the pozzolanic reaction earlier in the life (at 90 days for concrete made with TMM) of the concrete via hydrolysis of the GP and producing stronger concrete than the control [6,7].

The mechanical properties of fresh and hardened concrete using GP depend on the chemical composition, the diameter of the GP particles, and the curing conditions [8,9]. The mixing method used also contributes to the mechanical properties; the NMM allows for the partial dissolution o