scholarly journals Abrasion resistance of high early-strength concrete for rapid repair

2019 ◽  
Vol 289 ◽  
pp. 02002
Author(s):  
Nader Ghafoori ◽  
Matthew O. Maler ◽  
Meysam Najimi ◽  
Ariful Hasnat
Keyword(s):  
Compressive Strength ◽  
Abrasion Resistance ◽  
Wear Test ◽  
Cement Concrete ◽  
Rapid Repair ◽  
Strength Concrete ◽  
Type Iii ◽  
Resistance To Wear ◽  
Early Strength ◽  
Type V

This paper examines the abrasion resistance of high early-strength concrete developed for rapid repair of highways and bridge decks. The cement types chosen for this study included ASTM Type III, ASTM Type V, and Calcium Sulfoaluminate (CSA) cements. A cement content of 386 kg/m3 (650 lb/yd3) was maintained for all studied concretes. Test samples were tested after 24 hours and 28 days of curing in order to evaluate compressive strength and depth of wear. Test results revealed that the opening time to attain minimum required compressive strength for CSA cement concrete was one hour, whereas the values for Type V and Type III cement concretes were 8.5 and 6 hours, respectively. After 24 hours curing, CSA cement concrete displayed the highest strength, but lowest resistance to wear. The 28-day cured CSA cement concrete produced the highest strength and resistance to abrasion, while Type III cement concrete showed a similar strength, but lower resistance to wear, when compared to those of the Type V cement concrete.

scholarly journals Properties of high early-strength Type V cement concrete for rapid repair

2019 ◽  
Vol 289 ◽  
pp. 02003
Author(s):  
Nader Ghafoori ◽  
Matthew O. Maler ◽  
Meysam Najimi ◽  
Ariful Hasnat
Keyword(s):  
Compressive Strength ◽  
Strength Properties ◽  
Experimental Program ◽  
Cement Concrete ◽  
Freezing And Thawing ◽  
Rapid Repair ◽  
Type Iii ◽  
Chloride Migration ◽  
Early Strength ◽  
Type V

This study examines the suitability of ASTM Type V cement concrete for rapid repair applications. To this end, experimental results on transport and durability properties of high early-strength concretes using ASTM Type V cement were compared with those of a more traditional cement used for rapid repair, i.e. Type III cement. A cement content of 445 kg/m3 (750 lb/yd3) was maintained for all studied concretes. The experimental program included compressive strength, absorption, rapid chloride migration, corrosion resistance, and mass loss due to freezing and thawing regimes. The results of this study revealed that use of Type III and V cements were both effective for concrete rapid repair applications. The opening time to reach the minimum compressive strength of 21 MPa (3000 psi) was found dissimilar. Type III cement concrete showed better strength properties at early ages due to its high fineness. However, as curing age was extended to 24 hours and 28 days, Type V cement concrete produced higher strength results. Moreover, Type III cement concretes failed to display better performance in transport properties, corrosion, and frost resistance when compared to that of the studied Type V cement concretes.

Effects of Nano-CaCO3 on the Compressive Strength and Microstructure of High Strength Concrete in Different Curing Temperature

2011 ◽  
Vol 121-126 ◽  
pp. 126-131 ◽  
Author(s):  
Qing Lei Xu ◽  
Tao Meng ◽  
Miao Zhou Huang
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
High Strength Concrete ◽  
High Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Strength Concrete ◽  
Calcium Nitrite ◽  
Orientation Index ◽  
Early Strength

In this paper, effects of nano-CaCO3 on compressive strength and Microstructure of high strength concrete in standard curing temperature(21±1°C) and low curing temperature(6.5±1°C) was studied. In order to improve the early strength of the concrete in low temperature, the early strength agent calcium nitrite was added into. Test results indicated that 0.5% dosage of nano-CaCO3 could inhibit the effect of calcium nitrite as early strength agent, but 1% and 2% dosage of nano-CaCO3 could improve the strength of the concrete by 13% and 18% in standard curing temperature and by 17% and 14% in low curing temperature at the age of 3days. According to the XRD spectrum, with the dosage up to 1% to 2%, nano-CaCO3 can change the orientation index significantly, leading to the improvement of strength of concrete both in standard curing temperature and low curing temperature.

scholarly journals Autoclave-free ultra-early strength concrete preparation using an early strength agent and microstructure properties

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17369-17376
Author(s):  
Daosheng Sun ◽  
Ziwen Wang ◽  
Rui Ma ◽  
Aiguo Wang ◽  
Gaozhan Zhang
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Strength Concrete ◽  
Compressive Strength Of Concrete ◽  
Early Strength

In this study, nano calcium silicate hydrate was used as an early strength agent to promote the compressive strength of concrete at 1 day.

Properties of Phosphate Cement Mortar Used as Rapid-Repair Material

2011 ◽  
Vol 250-253 ◽  
pp. 1752-1756 ◽  
Author(s):  
Hong Wei Deng ◽  
Ying Zi Yang ◽  
Xiao Jian Gao
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
No Reduction ◽  
Cement Mortar ◽  
Magnesium Phosphate ◽  
Strength Development ◽  
Repair Material ◽  
Rapid Repair ◽  
Repair Materials ◽  
Early Strength

In order to determine the optimal proportion of magnesium phosphate cement mortar, the influences of ratio of magnesium phosphate cement-based binder (MPB) to sand (MPB/S), effects of fly ash on fluidity and strength development of MPB mortar, and the compatibility between MPB and traditional concrete and shrinkage of MPB mortar were investigated in this paper. The optimal proportion in this test was: setting adjusting agent of 12%, P/M ratio of 1:2(in weight), MPB/S ratio of 1:1 and FA/S ratio of 15%. The results showed that the MPB mortar met the higher early strength requirement of rapid-repair materials, with compressive strength beyond 50MPa and flexural strength more than 9.1MPa at 3 hours, and at later ages no reduction of strength happened. There was a good compatibility between MPB and traditional concrete. The shrinkage of MPB mortar at 28 days was less than 2.89 × 10-4. Therefore MPB is very suitable for rapid repairing of concrete structures.

scholarly journals Preparation and Application of Self-Curing Magnesium Phosphate Cement Concrete with High Early Strength in Severe Cold Environments

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5587
Author(s):  
Xingwen Jia ◽  
Jiayin Luo ◽  
Wenxin Zhang ◽  
Jueshi Qian ◽  
Junmeng Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Reaction Temperature ◽  
Magnesium Phosphate ◽  
Initial Reaction ◽  
Reaction Products ◽  
Cement Concrete ◽  
Cold Environments ◽  
Highly Active ◽  
Early Strength ◽  
Mixing Water

The early strength of magnesium phosphate cement (MPC) decreases sharply in severe cold environments ≤−10 °C, with the 2 h compressive strength falling to 3.5 MPa at−20 °C. Therefore, it cannot be used as a repair material for emergency repair construction in such environments. In this study, MPC is adapted for use in such cold environments by replacing part of the dead-burned magnesia (M) in the mixture with a small amount of light-burned magnesia (LBM) and introducing dilute phosphoric acid (PA) solution as the mixing water. The heat released by the highly active acid–base reaction of PA and LBM stimulates an MPC reaction. Moreover, the early strength of the MPC significantly improves with the increase in the Mg2+ concentration and the initial reaction temperature of the MPC paste, which enables MPC hardening in severe cold environments. Although the morphology of the reaction products of the MPC is poor and the grain plumpness and size of the struvite crystals are remarkably reduced, the early strength of MPC prepared in the severe cold environment is close to that of MPC prepared under normal temperature. Furthermore, the increases in the early reaction temperature and early strength of magnesium phosphate cement concrete (MPCC) are significantly improved when the PA concentration in the mixing water and the LBM/M ratio are 10% and 4–6% at −10 °C and 20% and 6–8% at −20 °C, respectively. Moreover, self-curing of MPCC can be realized even at −20 °C, at which temperature the 2 h and 24 h compressive strength of MPCC reach 36 MPa and 45 MPa, respectively.

Investigation of Workability and Compressive Strength of Wood Ash Cement Concrete Containing Nanosilica

2019 ◽  
Vol 1154 ◽  
pp. 129-136
Author(s):  
Akeem A. Raheem ◽  
Bolanle Deborah Ikotun
Keyword(s):  
Compressive Strength ◽  
Waste Product ◽  
Wood Ash ◽  
Biological Synthesis ◽  
Strength Development ◽  
Cement Concrete ◽  
Mix Proportion ◽  
Binder Ratio ◽  
Early Strength ◽  
Pozzolanic Cement

Studies have revealed that wood ash cement concrete just like other pozzolanic cement concrete has lower early strength compared to plain cement concrete. Nanoparticles have been found to improve the early strength of concrete due to its small size and large surface area. This paper reports the findings on influence of nanosilica on the workability and compressive strength of wood ash cement concrete. Wood ash was obtained as a waste product from Ladoke Akintola University of Technology (LAUTECH) bread bakery, Ogbomoso. Biological synthesis of nanosilica using kola pod extract and silica precursor (1:5) was conducted at Nanotechnology research group laboratory at LAUTECH. The chemical composition, specific gravity and grading of wood ash, fine and coarse aggregate used were determined. Concrete with 10% wood ash replacement for cement was produced using 1:2:4 mix proportion and water to binder ratio of 0.5. Nanosilica was added at 0.5, 1.0, 1.5 and 2.0% levels. Concrete with no wood ash and nanosilica served as the control. Workability and compressive strength of the plain and composite concrete were determined. The results showed that concrete workability was enhanced with introduction of nanosilica. The compressive strength also increased with the addition of nanosilica. Maximum compressive strength of 27.53MPa was achieved at 90 days with 1.5% nanosilica addition. It was concluded that nanosilica enhanced workability and improved both early and later strength development in wood ash concrete with 1.5% as the optimum addition.

The Influence of Super-Fine Steel Slag on the Properties of High-Strength Concrete

2013 ◽  
Vol 477-478 ◽  
pp. 941-944 ◽  
Author(s):  
Jing Jing Feng ◽  
Xiao Qing Wang ◽  
Shan Shan Wang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
High Strength Concrete ◽  
Steel Slag ◽  
High Strength ◽  
Cement Concrete ◽  
Strength Concrete ◽  
Good Ability

The properties of the concrete with super-fine steel slag were compared with those of the pure cement concrete. Results show that the concrete with 20% super-fine steel slag has similar compressive strength, elastic modulus, and permeability with the pure cement concrete at the age of 28 and 90 days. The addition of super-fine steel slag tends to decrease the initial slump of concrete, but it has a good ability of prevention of slump loss. The concrete with super-fine steel slag has similar anti-carbonation capacity with the pure cement concrete. The concrete with 30% super-fine steel slag has lower compressive strength, lower elastic modulus, and higher permeability than the pure cement concrete.

scholarly journals Influence of Nanosilica on Workability and Compressive Strength of Wood Ash Cement Concrete

2019 ◽  
Vol 2 (Issue 1) ◽  
Author(s):  
A.A Raheem ◽  
a Lateef ◽  
P.O Akinola ◽  
A.A Adeniyi ◽  
S.O Yusuf
Keyword(s):  
Compressive Strength ◽  
Waste Product ◽  
Wood Ash ◽  
Biological Synthesis ◽  
Strength Development ◽  
Cement Concrete ◽  
University Of Technology ◽  
Binder Ratio ◽  
Early Strength ◽  
Pozzolanic Cement

Studies have revealed that wood ash cement concrete just like other pozzolanic cement concrete has lower early strength compared to plain cement concrete. Nanoparticles have been found to improve the early strength of concrete due to its small size and large surface area. This paper reports the influence of nanosilica on the workability and compressive strength of wood ash cement concrete. Wood ash was obtained as a waste product from Ladoke Akintola University of Technology (LAUTECH) bread bakery, Ogbomoso. Biological synthesis of nanosilica using kola Pod extract and silica precursor (1:5) was conducted at Nanotechnology research group laboratory at LAUTECH. The chemical composition, specific gravity and particle size distribution of wood ash, fine and coarse aggregate used were determined. Concrete with 10% wood ash replacement for cement was produced using1:2:4mix proportion and water to binder ratio of 0.5.Nanosilica was added at 0.5, 1.0, 1.5 and 2.0% levels. Concrete with no wood ash and nanosilica served as the control. Workability and compressive strength of the plain and composite concrete were determined. The results showed that concrete workability was enhanced with introduction of nanosilica. The compressive strength also increased with addition of nanosilica. Maximum compressive strength of 27.53MP was achieved at 90 days with 1.5% nanosilica addition. It was concluded that nanosilica enhanced workability and improved both early and later strength development in wood ash concrete with 1.5% as the optimum addition.

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