دانلود رایگان مقاله انگلیسی اندازه گیری های کمی روش های عمل آوری برای عرشه پل بتنی - نشریه الزویر

abstract

This paper gives a quantitative comparison of how different curing methods impact the rate of drying and subsequent penetration of lime water and chloride penetration of concrete. Laboratory work is used to investigate a bridge deck concrete mixture cured by two different curing compounds, wet curing of different lengths, and then no curing. The results confirm that wet curing methods reduce the ingress of external chemicals more effectively. The wet curing for even one day provided significant improvement over both curing compounds and no curing. To confirm the findings in the field eight bridge decks were investigated that were cured with a curing compound and wet curing. The field investigation confirms the findings of the laboratory testing and emphasizes the importance of wet curing for long term durability of concrete. This paper provides important quantitative data that can be used to compare these methods and help with making decisions about different curing practices and the impact on the service life of concrete.

4. Conclusions

This work provides quantitative comparisons of the impact of different curing methods on the evaporation rate during drying, subsequent moisture uptake, and Cl penetration that can help practitioners decide how their construction practices impacts the durability of their concrete.

The following conclusive remarks can be made:

- The samples that were uncured showed the worst performance of the investigated samples.

- Wet curing significantly reduced the mass loss during drying, mass gain from sorption, and the penetration of NaCl solution.

- As the wet curing was increased then so was the durability performance in these tests; however, there was a little improvement after 7 days of wet curing with these materials and in this testing. This finding should be investigated with a wider range of materials before changes in practice are made.

- PAMS curing compound performed better than the lithium silicate curing compound in water retention during drying, and then the subsequent resistance of the microstructure to limewater and NaCl penetration.

- The drying rate in the field was higher for the lithium cured span of the bridge compared to the wet cured spans of the investigated bridge.

- The lithium silicate cured samples from the field showed higher Cl concentration and penetration depth compared to the wet cured samples for all seven bridges investigated.

This work concludes that wet curing is preferable over curing compounds for concrete if decreases in rate of drying, moisture penetration, and external chemicals are desirable. The reader should be careful in interpreting the results for the effectiveness of wet curing for different durations. Wet curing for longer durations is helpful to ensure that a minimum curing length is provided for a wide range of materials, construction practices, and weather.