Improving Freeze-Thaw Resistance and Strength Gain of Roller Compacted Fly Ash Concretes with Modified Absorbent Polymer

2018 ◽  
Vol 30 (3) ◽  
pp. 04018010 ◽  
Author(s):  
Huamei Yang ◽  
Zhen He ◽  
Yixin Shao ◽  
Lei Li
Keyword(s):  
Fly Ash ◽  
Strength Gain ◽  
Freeze Thaw ◽  
Absorbent Polymer

Study on Adding Super Absorbent Polymer to Improve the Frost Resistance of Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 960-963 ◽  
Author(s):  
De Zhi Wang ◽  
Yin Yan Zhang ◽  
Yun Fang Meng
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Frost Resistance ◽  
Strength Loss ◽  
Internal Curing ◽  
Super Absorbent Polymer ◽  
Freeze Thaw ◽  
Absorbent Polymer

Internal curing was especially beneficial to improve concrete performance. The super absorbent polymer and fly ash were used in the concrete and the frost resistance of concrete was studied. The result indicated that the super absorbent polymer changed the pore structure, increased the quantity of the pore, decreased the strength loss 5-10% after 250 freeze-thaw cycles and improved the frost resistance of concrete.

scholarly journals Freeze–Thaw Resistance and Air-Void Analysis of Concrete with Recycled Glass–Pozzolan Using X-ray Micro-Tomography

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 154
Author(s):  
Marija Krstic ◽  
Julio F. Davalos ◽  
Emanuele Rossi ◽  
Stefan C. Figueiredo ◽  
Oguzhan Copuroglu
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
The United States ◽  
Adsorption Method ◽  
X Ray ◽  
Freeze Thaw ◽  
Void System ◽  
Spatial Parameters ◽  
Micro Tomography ◽  
Air Void

Recent studies have shown promising potential for using Glass Pozzolan (GP) as an alternative supplementary cementitious material (SCM) due to the scarcity of fly ash and slag in the United States. However, comprehensive studies on the freeze–thaw (FT) resistance and air void system of mixtures containing GP are lacking. Therefore, this study aimed to evaluate GP’s effect on FT resistance and characterize mixtures with different GP contents, both macro- and microscopically. In this study, six concrete mixes were considered: Three mixes with 20%, 30% and 40% GP as cement replacements and two other comparable mixes with 30% fly ash and 40% slag, as well as a mix with 100% Ordinary Portland cement (OPC) as a reference. Concrete samples were prepared, cured and tested according to the ASTM standards for accelerated FT resistance for 1000 cycles and corresponding dynamic modulus of elasticity (Ed). All the samples showed minimal deterioration and scaling and high F/T resistance with a durability factor of over 90%. The relationships among FT resistance parameters, air-pressured method measurements of fresh concretes and air void analysis parameters of hardened concretes were examined in this study. X-ray micro-tomography (micro-CT scan) was used to evaluate micro-cracks development after 1000 freeze–thaw cycles and to determine spatial parameters of air voids in the concretes. Pore structure properties obtained from mercury intrusion porosimetry (MIP) and N2 adsorption method showed refined pore structure for higher cement replacement with GP, indicating more gel formation (C-S-H) which was verified by thermogravimetric analysis (TGA).

The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen
Keyword(s):  
Grain Size ◽  
Fly Ash ◽  
Cement Mortar ◽  
Setting Time ◽  
Mineralogical Composition ◽  
Cement Clinker ◽  
Strength Development ◽  
Fall Meeting ◽  
Freeze Thaw ◽  
Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

scholarly journals Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash

2018 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Longhui Wang ◽  
Yafeng Gong
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pervious Concrete ◽  
Early Age ◽  
Pavement Materials ◽  
Freeze Thaw ◽  
Replacement Method ◽  
Porosity And Permeability ◽  
Volume Method

Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.

scholarly journals Volume change behaviour and microstructure of stabilized loess under cyclic freeze–thaw conditions

2016 ◽  
Vol 43 (10) ◽  
pp. 865-874 ◽  
Author(s):  
Sheng-lin Wang ◽  
Qing-feng Lv ◽  
Hassan Baaj ◽  
Xiao-yuan Li ◽  
Yan-xu Zhao
Keyword(s):  
Fly Ash ◽  
Volume Change ◽  
Cement Content ◽  
Frost Heave ◽  
Equivalent Diameter ◽  
Surface Porosity ◽  
Change Rate ◽  
Freeze Thaw ◽  
Significant Damage ◽  
The Impact

Freeze–thaw action is considered to be one of the most destructive actions that can induce significant damage in stabilized subgrades in seasonally frozen loess areas. Laboratory tests including frost heave – thaw shrinkage and microstructure change during freeze–thaw cycles were conducted to evaluate the volume change rate of loess stabilized with cement, lime, and fly ash under the impact of cyclic freeze–thaw conditions. The loess specimens collapsed after eight freeze–thaw cycles (192 h), but most stabilized loess specimens had no visible damage after all freeze–thaw cycles were completed. All of the stabilized loess samples underwent a much smaller volume change than the loess alone after the freeze–thaw cycles. Although surface porosity and equivalent diameter of stabilized loess samples increased, the stabilized loess can retain its microstructure during freeze–thaw cycles when the cement content was less than 6%. To ensure freeze–thaw resistance of stabilized loess subgrades, the mix proportions of the three additives was recommended to be 4 to 5% cement, 6% lime, and 10% fly ash.

Study on the Influence of Freeze-Thaw on the Carbonation Property of Fly Ash Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 939-943 ◽  
Author(s):  
Jian Gang Niu ◽  
Liang Yan ◽  
Hai Tao Zhai
Keyword(s):  
Fly Ash ◽  
Laboratory Simulation ◽  
Influence Coefficient ◽  
Carbonation Depth ◽  
Freeze Thaw ◽  
Fly Ash Concrete ◽  
Concrete Carbonation ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

Based on the coupling testing program of freeze-thaw and carbonation, the laboratory simulation test is carried out. The laws of carbonation depth of the fly ash concrete suffered the freeze-thaw cycle in different test modes and the influence of fly ash dosage on concrete carbonation depth after the freeze-thaw cycle are studied. Defining the influence coefficient of the freeze-thaw cycles on carbonation depth of concrete, the mechanism of coupling of freeze-thaw and carbonation is analyzed,and the role of freeze-thaw and carbonation in the coupling process are obtained.

scholarly journals Durability of Portland Concrete Containing Polymeric Fillers and Fly Ash

2019 ◽  
Vol 26 (1) ◽  
pp. 103-108
Author(s):  
Witold BROSTOW ◽  
Nonso CHETUYA ◽  
Osman GENCEL ◽  
Hee Jae HONG ◽  
Noah MENARD ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Crack Propagation ◽  
Abrasive Wear ◽  
Brittle Failure ◽  
Wear Loss ◽  
Polymer Swelling ◽  
Wear Rates ◽  
Freeze Thaw ◽  
Acidic Degradation

Portland concrete suffers in service brittle failure, extensive crack propagation, and wear rates increasing with time. In spite of all the effort expended, these problems persisted when we had started our project. We used several polymeric fillers and fly ash. Higher compressive moduli than the starting concrete are seen for some compositions, the highest for 5 % of one of the polymers + 5 % fly ash. The same composition has the lowest Taber abrasive wear loss. All composites show lower wear loss values than Portland concrete. After 25 days of acidic degradation in 4.0 molar aq. HCl, the starting Portland concrete suffers stronger degradation that our composites. Polymer swelling mitigates acidic degradation. Repetitive freeze-thaw cycles between 15oF and 85oF show disappearance of the deep voids present before the first cycle in our composites—but not in the Portland cement. While the use of fly ash mitigates contamination of the environment, it is the combination of fly ash with polymers which provides significantly improved properties - tribological, chemical and mechanical ones – of the Portland concrete.

Empirical Prediction Models for Strength Gain Properties of Fly Ash Based Concrete Subjected to Accelerated Curing

2018 ◽  
Vol 1150 ◽  
pp. 73-90
Author(s):  
Vallarasu Manoharan Sounthararajan
Keyword(s):  
Fly Ash ◽  
Prediction Models ◽  
Pulse Velocity ◽  
Hot Water ◽  
Experimental Investigations ◽  
Strength Gain ◽  
Steam Curing ◽  
Empirical Prediction ◽  
Accelerated Curing ◽  
Water Curing

Experimental investigations on the early age, strength gain properties of fly ash blended cement concretes containing low and high volume fly ash replacement were studied. Concrete mixes were prepared with two different fly ash contents and varying concrete ingredients with water to binder ratio (w/b), fine to coarse aggregate ratio (F/c) and accelerator dosage. Five different curing techniques, namely controlled humidity curing; hot air oven curing, steam curing, hot water curing and normal water curing were adopted for curing the fly ash based concretes. Test results showed evidence the influence of accelerating admixtures and accelerated curing for obtaining the high early strength properties in fly ash mixed concrete. Most notably a maximum 1 day compressive strength of 40.20 MPa and 34.60 MPa with low (25%) and high (50%) volume fly ash concretes were obtained respectively in this study. Experimental results clearly indicated that the improvements on the strength gain properties with the careful selection of mix ingredients; accelerator addition and accelerated curing in fly ash based concrete mixes. Also, significant improvements on the flexural strength, elastic modulus, dynamic modulus and the ultrasonic pulse velocity test were noticed.

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