Retraction notice to “The effects of nanoparticles on early age compressive strength of ash-based geopolymers” [Ceramics International (2012) 4467–4476]

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.

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Characteristics of Hollow Compressed Earth Block Stabilized Using Cement, Lime, and Sodium Silicate

Civil and Environmental Engineering ◽

10.2478/cee-2021-0021 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Walid Edris ◽

Faris Matalkah ◽

Bara’ah Rbabah ◽

Ahmad Abu Sbaih ◽

Reham Hailat

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

Sodium Silicate ◽

Low Cost ◽

Construction Material ◽

Early Age ◽

Compressed Earth Block ◽

Earth Block ◽

Lower Production ◽

Northern Jordan

Abstract This research aims to produce a Compressed Earth Block (CEB) product using locally available soil collected from northern Jordan. The CEB mixture was further stabilized using Portland cement, lime, and sodium silicate. The research significance is based upon the urgent need of most developing countries (e.g. Jordan, Egypt…etc) to build more durable and low-cost houses by using locally available materials. As a result, CEB was identified as a cheap and environmentally friendly construction material. CEB specimens were thoroughly characterized by studying the mechanical properties and durability characteristics. Blocks of 30 x 15 x 8 cm with two holes of 7.5 cm in diameter have a potential for higher enduring, higher compressive strength, better thermal insulation, and lower production cost. Blocks were manufactured with an addition of 8 % for either Portland cement or lime, as well as 2 % of sodium silicate to the soil. The results showed that the addition of 8 % of cement to the CEB achieves satisfactory results in both mechanical and durability properties. Also, the addition of sodium silicate was found to enhance the early-age compressive strength however it affected negatively the durable properties of blocks by increasing the erosion rate and deterioration when exposed to water.

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Analysis of the Influence of Crystalline Admixtures at Early Age Performance of Cement-Based Mortar by Electrical Resistance Monitoring

Materials ◽

10.3390/ma14195705 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5705

Author(s):

Rubén Beltrán Cobos ◽

Fabiano Tavares Pinto ◽

Mercedes Sánchez Moreno

Keyword(s):

Compressive Strength ◽

Thermogravimetric Analysis ◽

Remote Monitoring ◽

Electrical Resistance ◽

Setting Time ◽

Early Age ◽

Resistance Monitoring ◽

Initial Setting Time ◽

Characterization Techniques ◽

Initial Setting

Crystalline admixtures are employed for waterproofing concrete. This type of admixtures can affect the early age performance of cement-based mixes. The electrical resistance properties of cement have been related to the initial setting time and to the hydration development. This paper proposes a system for remote monitoring of the initial setting time and the first days of the hardening of cement-based mortars to evaluate the effect of the incorporation of crystalline admixtures. The electrical resistance results have been confirmed by other characterization techniques such as thermogravimetric analysis and compressive strength measurements. From the electrical resistance monitoring it has been observed that the incorporation of crystalline admixtures causes a delay in the initial setting time and hydration processes. The measurements also allow to evaluate the influence of the amount of admixture used; thus, being very useful as a tool to define the optimum admixture dosage to be used.

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Comparison of ultrasonic wave reflection method and maturity method in evaluating early-age compressive strength of mortar

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2006.02.003 ◽

2006 ◽

Vol 28 (4) ◽

pp. 307-316 ◽

Cited By ~ 34

Author(s):

Thomas Voigt ◽

Zhihui Sun ◽

Surendra P. Shah

Keyword(s):

Compressive Strength ◽

Ultrasonic Wave ◽

Wave Reflection ◽

Early Age ◽

Reflection Method ◽

Maturity Method ◽

Ultrasonic Wave Reflection

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Mechanical Properties of Nano-Modified Cementitious Composites Reinforced with Single and Hybrid Fibers

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198120945692 ◽

2020 ◽

pp. 036119812094569

Author(s):

Riham Elhadary ◽

Mohamed T. Bassuoni

Keyword(s):

Compressive Strength ◽

Hybrid System ◽

Basalt Fiber ◽

Nano Particles ◽

Cementitious Composites ◽

Early Age ◽

Nano Silica ◽

Hybrid Fibers ◽

Cracking Behavior ◽

Flexural Performance

High-performance cementitious composites (HPCC) are prominently featured with high tensile ductility and toughness. Slag has been widely used in HPCC; however, HPCC with high volumes of slag has low matrix strength and limited development of micro-structure at early-age. These limitations can be mitigated by incorporating nano-particles (e.g., nano-silica) in the binder. The purpose of this study was to develop nano-modified HPCC with high ductility and matrix quality. A new form of basalt fibers termed basalt fiber pellets (BFP)—basalt fiber strands encapsulated by a polymeric resin—were used at different dosages (2.5% and 4.5% by volume), and in a hybrid system with PVA fibers (1% by volume) to develop in these composites. All composites incorporated a binder consisting of 50% general use cement and 50% slag with the addition of 6% nano-silica. The composites were tested in relation to compressive strength and flexural performance. All the nano-modified composites showed improved performance, especially at early-age, despite the high volume of slag incorporated in the binder. While the compressive strength of the mixtures was reduced with increasing the dosage of BFP, addition of 1% PVA fibers to BFP (hybrid system) enhanced the compressive strength of the composites. In the same context, the flexural performance of the composites comprising hybrid fibers was also improved in relation to flexural strength, post-cracking behavior, residual strength and toughness. Therefore, these composites have a promising potential for infrastructure applications requiring improved strength and ductility.

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Evaluation of Strengths from Cement Hydration and Slag Reaction of Mortars Containing High Volume of Ground River Sand and GGBF Slag

Advances in Civil Engineering ◽

10.1155/2019/4892015 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Punnaman Norrarat ◽

Weerachart Tangchirapat ◽

Smith Songpiriyakij ◽

Chai Jaturapitakkul

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Cement Hydration ◽

High Volume ◽

Inert Material ◽

Early Age ◽

Particle Sizes ◽

River Sand ◽

Reactive Material ◽

Median Particle

This paper investigates the cement hydration, and the slag reaction contributes to the compressive strengths of mortars mixed with ground river sand (GRS) and ground-granulated blast furnace (GGBF) slag with different particle sizes. GRS (inert material) and GGBF slag (reactive material) were ground separately until the median particle sizes of 32 ± 1, 18 ± 1, and 5 ± 1 micron and used to replace Portland cement (PC) in large amount (40–60%) by weight of the binder. The results showed that, at the early age, the compressive strength obtained from the cement hydration was higher than that obtained from the slag reaction. The results of compressive strength also indicated that the GGBF slag content and particle size play important roles in the slag reaction at the later ages, whereas cement hydration is more prominent at the early ages. Although the results could be expected from the use of GGBF slag to replace PC in mortar or concrete, this study had presented the values of the compressive strength along with ages and the finenesses of GGBF slag that contributed from cement hydration and from GGBF slag reaction.

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Investigation of the Relationship between Compressive Strength and Hydrate Formation Behavior of Low-Temperature Cured Cement upon Addition of a Nitrite-Based Accelerator

Materials ◽

10.3390/ma12233936 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3936 ◽

Cited By ~ 1

Author(s):

Jihoon Kim ◽

Daiki Honda ◽

Heesup Choi ◽

Yukio Hama

Keyword(s):

Compressive Strength ◽

Calcium Nitrate ◽

Hydrate Formation ◽

Strength Development ◽

Early Age ◽

Enhancement Effect ◽

Freezing Damage ◽

Formation Behavior ◽

Relative Production ◽

The Relationship

When concrete is used for construction in cold-temperature regions, cold-resistant accelerators based on calcium nitrite (Ca(NO2)2) and calcium nitrate (Ca(NO3)2) are added to prevent early freezing damage. Although cold-resistant accelerators increase the early compressive strength and prevent early freezing damage by promoting cement hydration, the strength enhancement effect owing to the formation of such hydrates has not been evaluated quantitatively thus far. This study covers various types of analysis to understand the relationship between cement hydrate formation behavior and strength development upon the addition of varying amounts of nitrite-based accelerator. We find that the early compressive strength is enhanced by the addition of nitrite-based accelerator via the promotion of the relative production of monosulfate and C-S-H in the early age. However, the development of compressive strength decreases with an increase in the curing age. Furthermore, we find that the promotion of hydration reactions at an early age with the addition of nitrite-based accelerator can affect the formation ratio of each hydrate at a late age. We believe our findings can significantly contribute to developments in concrete application and allied fields.

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