The production of portland cement–the key ingredient in concrete–generates a significant amount of carbon dioxide.However,due to its incredible versatility,availability,and relatively low cost,concrete is the most c...The production of portland cement–the key ingredient in concrete–generates a significant amount of carbon dioxide.However,due to its incredible versatility,availability,and relatively low cost,concrete is the most consumed manmade material on the planet.One method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement.This study presents the results of an experimental investigation that evaluates effect of fly ash replacement level on the fracture energy of concrete.This study includes four mixes with 0%,30%,50%,and 70%fly ash as a cement replacement.This experimental program consisted of 32 fracture beams to study the fracture behavior of concrete.The experimental fracture energies were compared with the fracture energy provisions of different design codes and also different analytical equations.Furthermore,statistical data analyses(parametric and non-parametric)were performed to evaluate whether or not there is any statistically significant difference between the experimental fracture energies of different mixes.Results of these statistical tests show that the mix with higher level of fly ash replacement level has higher fracture energy.展开更多
This study presents the results of an experimental investigation that compares the mechanical properties, fracture behavior, creep, and shrinkage of a chemically-based self-consolidating concrete （SCC） mix with that...This study presents the results of an experimental investigation that compares the mechanical properties, fracture behavior, creep, and shrinkage of a chemically-based self-consolidating concrete （SCC） mix with that of a corresponding conventional concrete （CC） mix. The CC and SCC mix designs followed conventional proportioning in terms of aggregate type and content, cement content, air content, water-cementitiuos materials （w/cm） ratio, and workability. Then, using only chemical admixtures, the authors converted the CC mix to an SCC mix with all of the necessary passing, filling, flowability, and stability requirements typically found in SCC. The high fluidity was achieved with a polycarboxylate-based high-range water-reducing admixture, while the enhanced stability was accomplished with an organic, polymer-based viscosity-modifying admixture. The comparison indicated that the SCC and CC mixes had virtually identical tensile splitting strengths, flexural strengths, creep, and shrinkage. However, the SCC mix showed higher compressive strengths and fracture energies than the corresponding CC mix.展开更多
Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked ...Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked bridge decks each year. To design an appropriate mixture for crack free bridge deck, it is important to study previous researches. This paper presents a comprehensive literature review of the performance of different materials compositions as well as methods have been used to reduce and control bridge deck cracks. Different material compositions and methods are discussed in terms of their performances as well as advantages and disadvantages.展开更多
文摘The production of portland cement–the key ingredient in concrete–generates a significant amount of carbon dioxide.However,due to its incredible versatility,availability,and relatively low cost,concrete is the most consumed manmade material on the planet.One method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement.This study presents the results of an experimental investigation that evaluates effect of fly ash replacement level on the fracture energy of concrete.This study includes four mixes with 0%,30%,50%,and 70%fly ash as a cement replacement.This experimental program consisted of 32 fracture beams to study the fracture behavior of concrete.The experimental fracture energies were compared with the fracture energy provisions of different design codes and also different analytical equations.Furthermore,statistical data analyses(parametric and non-parametric)were performed to evaluate whether or not there is any statistically significant difference between the experimental fracture energies of different mixes.Results of these statistical tests show that the mix with higher level of fly ash replacement level has higher fracture energy.
文摘This study presents the results of an experimental investigation that compares the mechanical properties, fracture behavior, creep, and shrinkage of a chemically-based self-consolidating concrete （SCC） mix with that of a corresponding conventional concrete （CC） mix. The CC and SCC mix designs followed conventional proportioning in terms of aggregate type and content, cement content, air content, water-cementitiuos materials （w/cm） ratio, and workability. Then, using only chemical admixtures, the authors converted the CC mix to an SCC mix with all of the necessary passing, filling, flowability, and stability requirements typically found in SCC. The high fluidity was achieved with a polycarboxylate-based high-range water-reducing admixture, while the enhanced stability was accomplished with an organic, polymer-based viscosity-modifying admixture. The comparison indicated that the SCC and CC mixes had virtually identical tensile splitting strengths, flexural strengths, creep, and shrinkage. However, the SCC mix showed higher compressive strengths and fracture energies than the corresponding CC mix.
文摘Early age cracking on bridge deck has been the subject of many studies for years. Cracking is a major concern because it leads to premature deterioration of structures. Millions of dollars spent to repair the cracked bridge decks each year. To design an appropriate mixture for crack free bridge deck, it is important to study previous researches. This paper presents a comprehensive literature review of the performance of different materials compositions as well as methods have been used to reduce and control bridge deck cracks. Different material compositions and methods are discussed in terms of their performances as well as advantages and disadvantages.
