Study on Long Term Performance of Concrete of Slag-Alkali Higher Calcium Fly Ash

2006 ◽  
Vol 302-303 ◽  
pp. 98-104
Author(s):  
Ming Tang ◽  
Xiao Li
Keyword(s):  
Fly Ash ◽  
Orthogonal Design ◽  
Concrete Specimen ◽  
Mixture Ratio ◽  
Dispersion Degree ◽  
Set Up ◽  
Long Term Performance ◽  
Term Performance ◽  
Mixture Ratio Design

The slag-alkali is used to activate the activity of higher calsium fly ash. By the designs of the mixture ratio and the quadratic regression orthogonal design, the best combination is sought out. Several mixture factors which affect the rule of the concrete material properties and long term performance are researched. The mathematic models which are set up by the mixture ratio design with the quadralic regression orthogonal design can be effective. The precision is high. The strength of the concrete of slag-alkali fly ash was still increasing after 8 year. The dispersion degree of those specimens is small. The SEM photo of cracked specimen and early concrete specimen shows the surface of fly ash in 7 days concrete is slick and that in 8 years old specimen has been enwrapped tightly by much hydrate plant.

scholarly journals Seasonal Performance Evaluation of Pavement Base Using Recycled Materials

2021 ◽  
Vol 13 (22) ◽  
pp. 12714
Author(s):  
Yang Zhang ◽  
Bora Cetin ◽  
Tuncer B. Edil
Keyword(s):  
Fly Ash ◽  
Recycled Concrete ◽  
Ride Quality ◽  
Concrete Aggregate ◽  
Traffic Loading ◽  
Pavement Base ◽  
Natural Aggregates ◽  
Long Term Performance ◽  
Term Performance

Using recycled pavement materials to construct new pavement base is currently an important construction strategy bringing improved sustainability. This study investigates the long-term performance of pavement bases constructed with recycled concrete aggregate (RCA), reclaimed asphalt pavement (RAP), and blends with natural aggregates in a seasonal frost region. The stabilization effect of fly ash on RAP was studied as well. In situ falling weight deflectometer (FWD) tests were routinely conducted to provide seasonal deflection data, which were used to back-calculate the layer modulus. Seasonal changes in the base layer modulus along with the pavement ride quality were monitored. One of the two lanes at the test sections was consistently subjected to traffic loading, whereas the other one was not. Findings from this field research indicated that after undergoing over 8 years of naturally seasonal freeze-thaw conditions, 100% RCA, 50% RCA, plus 50% natural aggregates, and 100% RAP, presented improved performance over 100% natural aggregates. However, 50% RAP blended with 50% natural aggregates performed comparably to natural aggregates only, and fly ash did not provide considerable improvement on the long-term performance of 50% RAP plus 50% natural aggregate base. Seasonal climatic variations turned out to affect pavement performance more critically than traffic loading.

The Effect of Fly Ash on Water Transport of Concrete in Dry State

2011 ◽  
Vol 335-336 ◽  
pp. 1190-1194
Author(s):  
Xiong Wen Zhang ◽  
Lei Jiang ◽  
Guan Guo Liu
Keyword(s):  
Fly Ash ◽  
Water Transport ◽  
High Performance ◽  
Test Results ◽  
Paper Test ◽  
Environment Friendly ◽  
Promising Solution ◽  
Long Term Performance ◽  
Term Performance

Water transport is an important parameter that affects the long term performance and degradation of concrete greatly. Nowadays, adding fly ash is a promising solution to achieve high-performance, low-price and environment-friendly concrete. To characterize the effect of fly ash on water transport of concrete, especially in dry state, moisture variations and microstructure of concrete with different mix proportions were studied in this paper. Test results reveal that fly ash will increase the porosity of early curing concrete, the higher porosity leads to a faster evaporation, which accelerates the transport of water in cement based materials.

scholarly journals Development of Test Equipment for Evaluating Hydraulic Conductivity of Permeable Block Pavements

2018 ◽  
Vol 10 (7) ◽  
pp. 2549 ◽  
Author(s):  
Jaehun Ahn ◽  
Aryssa Marcaida ◽  
Yoongeun Lee ◽  
Jongwon Jung
Keyword(s):  
Low Impact Development ◽  
Test System ◽  
Silica Sand ◽  
Small Scale ◽  
Pavement Materials ◽  
Constant Head ◽  
Set Up ◽  
Long Term Performance ◽  
Term Performance

The use of permeable block pavement has been acknowledged as one of the promising Low Impact Development (LID) strategies to mitigate the harmful effects of depletion of natural surfaces, due to the uncontrollable development of infrastructure and buildings. Numerous studies, associated with drainage properties and long-term performance of this traditional pavement alternative, have been conducted in the past 30 years. Nevertheless, standardized equipment and methodologies are still limited, specifically for small-scale laboratory models. This paper suggests equipment that is capable of evaluating the hydraulic performance of permeable pavement materials in a laboratory set-up, by monitoring permeability and simulating the physical clogging process. Constant head permeability tests with systematic application of fine clogging particles were conducted on three identical permeable block systems (PBS), composed of four stone pavers. Each test system received an equivalent amount of eight years’ particle loading of silica sand, with different size distributions. The experimental results revealed that all the models showed permeability degradation trends similar to those presented in other literature.

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