scholarly journals The Relationship of Compressive Strength and Chemically Bound Water Content of High-Volume Fly Ash-Cement Mortar

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6273
Author(s):  
Chunping Gu ◽  
Jikai Yao ◽  
Yang Yang ◽  
Jie Huang ◽  
Linhao Ma ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Content ◽  
Cement Mortar ◽  
Bound Water ◽  
High Volume ◽  
Strength Development ◽  
Cement Based Materials ◽  
The Relationship ◽  
Bound Water Content

Fly ash (FA) has been widely used in cement-based materials, but limited work has been conducted to establish the relationship between the compressive strength and hydration process of high-volume FA (HVFA)-cement-based material. In this study, the compressive strength and chemically bound water contents of FA-cement-based materials with different water-to-binder ratios (0.4, 0.5, and 0.6) and FA contents (0%, 30%, 40%, 50%, 60%, and 70%) were tested. Replacing more cement with FA reduced the compressive strength and of HVFA-cement-based materials. The compressive strength and chemically bound water content reduced by about 60–70% when 70% cement was replaced by FA. Water-to-binder ratio showed more significant influence on the chemically bonded water at later ages than that at early ages. Based on test results, the prediction equation of chemically bound water content was established, and its accuracy was verified. The error was less than 10%. The relationship between the compressive strength and chemically bound water content was also fitted. The compressive strength and chemically bound water content showed linear relationships for different water-to-binder ratios, hence the compressive strength of HVFA-cement mortar could be predicted with the chemically bound water content and water-to-binder ratios. The results of this study could be used for the prediction of the compressive strength development of HVFA-cement mortars, and is helpful to develop the mix design method of HVFA-cement-based materials.

scholarly journals Strength Development and Thermogravimetric Investigation of High-Volume Fly Ash Binders

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3344 ◽  
Author(s):  
Zhiyuan Zhou ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Rackel San Nicolas ◽  
Gideon Hadi Kusuma ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Temperature Rise ◽  
Bound Water ◽  
High Volume ◽  
Heat Of Hydration ◽  
New Method ◽  
Hydration Properties ◽  
Adiabatic Temperature Rise ◽  
High Volume Fly Ash

To address sustainability issues by facilitating the use of high-volume fly ash (HVFA) concrete in industry, this paper investigates the early age hydration properties of HVFA binders in concrete and the correlation between hydration properties and compressive strengths of the cement pastes. A new method of calculating the chemically bound water of HVFA binders was used and validated. Fly ash (FA) types used in this study were sourced from Indonesia and Australia for comparison. The water to binder (w/b) ratio was 0.4 and FA replacement levels were 40%, 50% and 60% by weight. Isothermal calorimetry tests were conducted to study the heat of hydration which was further converted to the adiabatic temperature rise. Thermo-gravimetric analysis (TGA) was employed to explore the chemically bound water (WB) of the binders. The results showed that Australian FA pastes had higher heat of hydration, adiabatic temperature rise, WB and compressive strength compared to Indonesian FA pastes. The new method of calculating chemically bound water can be successfully applied to HVFA binders. Linear correlation could be found between the WB and compressive strength.

Effect of steam curing on compressive strength and microstructure of high volume ultrafine fly ash cement mortar

2021 ◽  
Vol 266 ◽  
pp. 120894
Author(s):  
Jin Yang ◽  
Huachao Hu ◽  
Xingyang He ◽  
Ying Su ◽  
Yingbin Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Mortar ◽  
High Volume ◽  
Steam Curing

scholarly journals Influence of Mechanical and Mineralogical Activation of Biomass Fly Ash on the Compressive Strength Development of Cement Mortars

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6654
Author(s):  
Jakub Popławski ◽  
Małgorzata Lelusz
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Mortar ◽  
Setting Time ◽  
Green Energy ◽  
Biomass Combustion ◽  
Strength Development ◽  
Compressive Strength Development ◽  
Biomass Fly Ash

Biomass combustion is a significant new source of green energy in the European Union. The adequate utilization of byproducts created during that process is a growing challenge for the energy industry. Biomass fly ash could be used in cement composite production after appropriate activation of that material. This study had been conducted to assess the usefulness of mechanical and physical activation methods (grinding and sieving), as well as activation through the addition of active silica in the form of silica fume, as potential methods with which to activate biomass fly ash. Setting time, compressive strength, water absorption and bulk density tests were performed on fresh and hardened mortar. While all activation methods influenced the compressive strength development of cement mortar with fly ash, sieving of the biomass fly ash enhanced the early compressive strength of cement mortar. The use of active silica in the form of silica fume ensured higher compressive strength results than those of control specimens throughout the entire measurement period.

scholarly journals Compressive Strength Development of High-Volume Fly Ash Ultra-High-Performance Concrete under Heat Curing Condition with Time

2020 ◽  
Vol 10 (20) ◽  
pp. 7107
Author(s):  
Pham Sy Dong ◽  
Nguyen Van Tuan ◽  
Le Trung Thanh ◽  
Nguyen Cong Thang ◽  
Viet Hung Cu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Strength Development ◽  
Ultra High Performance Concrete ◽  
Heat Curing ◽  
Compressive Strength Development ◽  
Curing Condition

This research investigated the effect of fly ash content on the compressive strength development of ultra-high-performance concrete (UHPC) at different curing conditions, i.e., the standard curing condition and the heat curing. A total of 20 mixtures were prepared to cast specimens to measure the compressive strength at different ages from 3 days to 180 days. Additionally, 300 specimens were prepared to estimate the appropriate heat curing period at the early ages in terms of enhancing the 28-day compressive strength of UHPC with high content of fly ash (FA). From the regression analysis using test data, empirical equations were formulated to assess the compressive strength development of UHPC considering the FA content and maturity function. Test results revealed that the preference of the addition of FA for enhancing the compressive strength of UHPC requires the early heat curing procedure which can be recommended as at least 2 days under 90 °C. Moreover, the compressive strength of UHPC with FA under heat curing mostly reached its 28-day strength within 3 days. The proposed models based on the fib 2010 model can be a useful tool to reliably assess the compressive strength development of UHPC with high-volume fly ash (HVFA) (up to 70% fly ash content) under a heat curing condition that possesses a different performance from that of normal- and high-strength concrete. When 50% of the cement content was replaced by FA, the embodied CO2 emission for UHPC mixture reduced up to approximately 50%, which is comparable to the CO2 emission calculated from the conventional normal-strength concrete.

Effect of humic acid on the behaviour of solidified dredged material

2009 ◽  
Vol 46 (9) ◽  
pp. 1093-1099 ◽  
Author(s):  
Wei Zhu ◽  
C. F. Chiu ◽  
Chun-Lei Zhang ◽  
Ke-Lin Zeng
Keyword(s):  
Compressive Strength ◽  
Humic Acid ◽  
Water Content ◽  
Acid Content ◽  
Unconfined Compressive Strength ◽  
Bound Water ◽  
Dredged Material ◽  
Curing Time ◽  
Unconfined Compression ◽  
Bound Water Content

Unconfined compression and bound-water content tests were conducted to study the effect of humic acid on the mechanical behaviour of solidified dredged material. It is found that the unconfined compressive strength (qu) and the change in bound-water content (Δmbw) exhibit similar relationships with the humic-acid content and curing time. Both parameters decrease with an increase in humic-acid content until reaching a threshold humic-acid content, above which the magnitudes of both parameters reduce to relatively low and steady values. In addition, both qu and Δmbw increase nonlinearly with the curing time. A relationship between qu and Δmbw is presented; Δmbw may reflect the extent of the hydrates developed in the solidified soil which increases nonlinearly with qu.

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 High Strength Geopolymers Produced from Coal Combustion Fly Ash

2013 ◽  
Vol 11 (2) ◽  
pp. 155-161
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coal Combustion ◽  
High Strength ◽  
Coarse Fraction ◽  
Strength Development ◽  
Fly Ashes ◽  
The Relationship ◽  
Geopolymer Material

High strength geopolymers were produced from coal combustion fly ashes. These matrices reached compressive strength values over 100 MPa, much stronger and denser than obtained by using Portland Cement binders. Size fractions were obtained by size separation techniques and the relationship between strength and particle size was investigated. The differences in compressive strength measured in the geopolymers made from fine fractions, the original fly ash and a coarse fraction of the same ash, were not significantly higher than the variation found for a reference geopolymer material. Therefore, a direct size-strength relationship could not be proven. Moreover, the chemistry and the pH of the fractions also varied, and this might as well has played a role in the strength development.

Effect of Nano Silica and Ultrafine Fly Ash on Compressive Strength of High Volume Fly Ash Mortar

2013 ◽  
Vol 368-370 ◽  
pp. 1061-1065 ◽  
Author(s):  
Steve W.M. Supit ◽  
Faiz U.A. Shaikh ◽  
Prabir K. Sarker
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Volume ◽  
Partial Replacement ◽  
Strength Development ◽  
Test Results ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
High Volume Fly Ash ◽  
Class F Fly Ash

This paper evaluates the effect of Ultrafine Fly Ash (UFFA) and nanoSilica (NS) on compressive strength of high volume fly ash (HVFA) mortar at 7 days and 28 days. Three series of mortar mixes are considered in the first part of this study. In the first series the effect of high content of class F fly ash as partial replacement of cement at 40, 50 and 60% (by wt.) are considered. While in the second and third series, the UFFA and NS are used as partial replacement of cement at 5%, 8%, 10%, 12% and 15% and 1%, 2%, 4%, 6% and 8% (by wt.) of cement, respectively. The UFFA and the NS content which exhibited highest compressive strength in the above series are used in the second part where their effects on the compressive strength of HVFA mortars are evaluated. Results show that the mortar containing 10% UFFA as partial replacement of cement exhibited the highest compressive strength at both 7 and 28 days among all UFFA contents. Similarly, the mortar containing 2% NS as partial replacement of cement exhibited the best performance. Interestingly, the use of UFFA in HVFA mortars did not improve the compressive strength. However, the use of 2% and 4% NS showed improvement in the compressive strength of HVFA mortar containing 40% and 50% fly ash at both ages. The effects of NS and UFFA on the hydration and strength development of HVFA mortar is also evaluated through X-Ray Diffraction (XRD) test. Results also show that the UFFA and NS can significantly reduce the calcium hydroxide (CH) in HVFA mortars.

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