Effect of water curing conditions on the hydration degree and compressive strengths of fly ash–cement paste

2006 ◽  
Vol 28 (9) ◽  
pp. 781-789 ◽  
Author(s):  
Pipat Termkhajornkit ◽  
Toyoharu Nawa ◽  
Kiyofumi Kurumisawa
Keyword(s):  
Fly Ash ◽  
Cement Paste ◽  
Hydration Degree ◽  
Curing Conditions ◽  
Effect Of Water ◽  
Water Curing

HYDRATION KINETICS OF CEMENT PASTE WITH SILICA FUME AND FLY ASH

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Miguel Picornell ◽  
Sameer Hamoush ◽  
Taher Abu-Lebdeh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Regional Analysis ◽  
Testing Machine ◽  
Testing System ◽  
Hydration Kinetics ◽  
Curing Conditions ◽  
Water Curing

This research study investigates the effect of fly ash and silica fume on the cement paste hydration. A total of 350 samples of different percentages of each additive were tested and compared with the controlled cement paste without additives. Testing method includes water curing and vacuum curing conditions and involves the use of Forney Universal Testing Machine and MTS Landmark Servohydraulic Testing System (MTS) for compressive strength; Fourier Transfer Infrared Spectroscopy (FTIR) monitored the hydration with spectra; and Scanning Electron Microscope (SEM) generated images for regional analysis. Compressive strength testing demonstrated that silica fume replacement had the highest overall strength under water curing. Replacement of fly ash exhibited the highest overall strength under vacuum curing. The hydration process was monitored with the use of FTIR and SEM. Signatures of CSH which produce most of the concretes’ strength, has been determined and examined from 3 to 56 days. FTIR and SEM testing showed an increase in the change of CSH area with age. SEM testing revealed the formation of pores, CSH, and CH in images at all ages. The area of CSH grows most in early ages and diminishes over time. It is clear that the method of curing makes a difference in hydration. Results indicated that the area at which the possible formation of CSH was determined from each sample, has increased with respect to time; signifying the increase in strength over the course of testing days.

Influences of Initial Curing Conditions on the Microstructure of Fly Ash Cement System

2010 ◽  
Vol 168-170 ◽  
pp. 532-536 ◽  
Author(s):  
Guo Li ◽  
En Li Lu ◽  
Peng Wang ◽  
Ou Geng ◽  
Yong Sheng Ji
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Mortar ◽  
Early Age ◽  
Concrete Durability ◽  
Cement Concrete ◽  
Hydration Degree ◽  
Curing Conditions ◽  
Cement System ◽  
C 30

In order to study the influences of initial curing conditions on fly ash (FA) cement concrete durability, fly ash cement samples with 30% replacement ratio were fabricated and cured in water at 10°C, 20°C, 30°Cand 40°C for 3d, 7d, 14d and 28d respectively. Hydration degrees of fly ash at early age were measured using the selective dissolve method. Correspondingly the pore structure and morphology of FA-cement mortar and compared cement mortar were studied by using MIP and SEM methods. Then early age compressive strengths of FA-cement concrete and compared normal cement concrete were tested. Experimental results show that initial curing temperatures and ages are important factors to fly ash early age hydration degree, FA-cement system microstructure, morphology and early age compressive strength etc. High curing temperatures and longer curing time can lead higher fly ash hydration degree, and then higher compressive strength of FA-cement concrete, and make the micro-structures of fly ash-cement system denser.

scholarly journals Compressive Strength Performance of Alkali Activated Concretes under Different Curing Conditions

2021 ◽  
Author(s):  
Anıl Niş ◽  
İlhan Altındal
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Strength Performance ◽  
Curing Conditions ◽  
Standardization Process ◽  
Water Curing ◽  
Curing Regimes ◽  
Alkali Activated Concrete ◽  
Alkali Activated ◽  
Ambient Curing

This study investigated the influence of different curing conditions on the compressive strength (CS) of the different alkali activated concrete (AAC) specimens at the ages of 2, 28, and 90 days for the structural utilization and standardization process of AAC instead of OPC concrete. For this aim, 100% slag (S100), 75% slag and 25% fly ash (S75FA25), and 50% slag and 50% fly ash based (S50FA50) AAC specimens were produced. Based on the oven-curing (O), water-curing (W), and ambient-curing (A) methods, the influence of 2O for 2 days, 26A2O, 2O26A, 28A, 28W, 26W2O, and 2O26W for 28 days, and 88A2O, 2O88A, 90A, 88W2O, 2O88W, 90W for 90 days on the CS of the AAC were examined in details. In addition, the influence of delayed oven-curing conditions on CS development was also investigated. The results indicated that curing conditions significantly affected on the CS and the water-curing condition could provide a better CS for those of AAC at 90 days. Although, the oven-curing enhanced CS of the S100 specimens at initial ages (first oven-curing applied), delayed oven-curing (oven-curing applied later) was found significant for S75FA25 and S50FA50 specimens. The delayed oven-curing affected more on the CS of the AAC when fly ash content increased. The most of AAC specimens with oven-curing had significantly enhanced the CS at 28 days, but S50FA50 at the age of 90 days decreased. Different curing regimes were proposed for the superior compressive strength values for each AAC specimens at the ages of 28 and 90 days.

scholarly journals Pengaruh Air Laut sebagai Air Pencampur dan Air Perawatan pada Karakteristik Pasta Semen dan Mortar

2018 ◽  
Vol 5 (1) ◽  
pp. 28
Author(s):  
Adiwijaya Ali ◽  
Irka Tangke Datu
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Cement Paste ◽  
Tap Water ◽  
Fine Aggregate ◽  
Curing Conditions ◽  
Composite Cement ◽  
Water Characteristics ◽  
Water Curing ◽  
Mixing Water

The goal of this research is to investigate the influence of seawater as mixing water and curing water on characteristics of cement paste and mortar. Research was conducted with making mixtures of cement paste and mortar using two kind of cement, Portland Composite Cement (PCC) and Pozzolana Portland Cement (PPC) with seawater as mixing water. Characteristics of fine aggregate and characteristics of cement paste with seawater mixing were investigated. Furthermore, 144 cube mortar specimens in size of 5 cm x 5 cm x 5 cm in four series mortar mixtures were casted according with SNI 03-6825-2002. At 24 hours after specimens were casted, cube mortar specimens were cured in tap water curing (TC), seawater curing (SC) and air curing (AC). After achievement at certain curing day of 3, 7, 14 and 28 days, cube mortar samples were tested in compressive strength. Results concluded that seawater mixing improves compressive strength of mortar up to 28 days in all curing conditions, TC, SC and AC. Moreover, strength of mortar is not affected by type of curing water, tap water or seawater.

Effect of Initial Curing Conditions on Thaumasite Form of Sulfate Attack of Cement Based Materials

2013 ◽  
Vol 275-277 ◽  
pp. 2136-2140 ◽  
Author(s):  
Chang Hui Yang ◽  
Xiao Bin Xiang ◽  
Ben Wan Liu ◽  
Jing Zhang
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Sulfate Attack ◽  
X Ray Diffraction ◽  
Hydration Degree ◽  
Humid Air ◽  
Curing Conditions ◽  
X Ray ◽  
Cement Based Materials ◽  
Water Curing

The effects of initial high humid air-curing, standard water-curing and sealed-curing on thaumasite form of sulfate attack (TSA) of cement based materials were studied. The erosion products after three years attack in 5% MgSO4 solution were analyzed by means of X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). Initial high humid air-curing can delay the TSA of specimens for CaCO3 generated by carbonation and filled in the pores of the specimens, forming a compacted surface and restricting the intrusion of SO42-. In comparison, specimens cured in sealed condition occurred TSA most serious resulting from that large amount of inter-defects in specimens for the lower hydration degree, and SO42- ions could intrude into specimens more easily.

scholarly journals Effect of Mix Constituents and Curing Conditions on Compressive Strength of Sustainable Self-Consolidating Concrete

2019 ◽  
Vol 11 (7) ◽  
pp. 2094 ◽  
Author(s):  
Osama Ahmed Mohamed
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Stability Index ◽  
Strength Development ◽  
Self Consolidating Concrete ◽  
Curing Conditions ◽  
Practical Applications ◽  
Water Curing ◽  
Curing Method

The production of cement requires significant energy and is responsible for more than 5% of global CO2 emissions; therefore it is imperative to reduce the production and use of ordinary portland cement (OPC). This paper examines the compressive strength development of low water-to-binder (w/b) ratio self-consolidating concrete (SCC) in which 90% of the cement is replaced with industrial by-products including ground granulated blast furnace slag (GGBS), fly ash, and silica fume. The emphasis in this paper is on replacing a large volume of cement with GGBS, which represented 10% to 77.5% of the cement replaced. Fresh properties at w/b ratio of 0.27 were examined by estimating the visual stability index (VSI) and t50 time. The compressive strength was determined after 3, 7, 28, and 56 days of curing. The control mix made with 100% OPC developed compressive strength ranging from 55 MPa after three days of curing to 76.75 MPa after 56 days of curing. On average, sustainable SCC containing 10% OPC developed strength ranging from 31 MPa after three days of curing to 56.4 MPa after 56 days of curing. However, the relative percentages of fly ash, silica fume, and GGBS in the 90% binder affect the strength developed as well. In addition, this paper reports the effect of the curing method on the 28 day compressive strength of environmentally friendly SCC in which 90% of the cement is replaced by GGBS, silica fume, and fly ash. The highest compressive strength was achieved in samples that were cured for three days under water, then left to air-dry for 25 days, compared to samples cured using chemical compounds or samples continuously cured under water for 28 days. The study confirms that SCC with 10% OPC and 90% supplementary cementitious composites (GGBS, silica fume, fly ash) can achieve compressive strength sufficient for many practical applications by incorporating high amounts of GGBS. In addition, air-curing of samples in a relatively high temperature (after three days of water curing) produce a higher 28 day compressive strength compared to water curing for 28 days, or membrane curing.

Evolution of Capillary Porous Structure in Steam Curing Concrete with Mineral Admixtures

2012 ◽  
Vol 450-451 ◽  
pp. 3-7
Author(s):  
Ming Fang Ba ◽  
Chun Xiang Qian
Keyword(s):  
Fly Ash ◽  
Porous Structure ◽  
Evolution Model ◽  
Mineral Admixtures ◽  
Porous Structures ◽  
Capillary Porosity ◽  
Hydration Degree ◽  
Steam Curing ◽  
Curing Conditions ◽  
Cast Concrete

The capillary porous structures of the pre-cast concrete with different initial steam-curing duration were analyzed with MIP techniques. Then the hydration degree of cement, fly ash and slag in pre-cast concrete versus time were obtained respectively by combing the hydrochlorides and EDTA selecting dissolution methods, based on which the corresponding evolution of capillary porosity was determined. The comparison between calculated results and experimental capillary porosity showed that the proposed evolution model of capillary porosity could be adopted to reveal the developing trend of capillary porosity of pre-cast concrete with fly ash and slag under certain curing conditions

Restricted Hydration of Mass-Cured Concrete Containing Fly Ash

1986 ◽  
Vol 85 ◽  
Author(s):  
R. H. Mills ◽  
N. Buenfeld
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Portland Cement ◽  
Cement Paste ◽  
Strength Loss ◽  
Surface Strength ◽  
Curing Conditions ◽  
Evaporable Water

ABSTRACTCement paste and concrete specimens containing three different mixtures of portland cement (PC) and high-lime fly ash (FA) were subjected to various curing conditions, and the strengths, non-evaporable water, and porosities compared with control mixes containing portland cement only. Strength and porosity data indicated that the cementing action of the mixtures was in all cases inferior to portland cement. For each mixture the strength loss resulting from imperfect curing, i.e. sealed or exposed to 50% relative humidity, was greater than for portland cement. In the case of concrete drying from one surface, strength differences were found, but these were not as clearly defined as those obtained in the paste specimens.

Effect of Cuing Conditions on the Microstructural Characteristics of Complex Binders

2013 ◽  
Vol 756-759 ◽  
pp. 29-32
Author(s):  
Xiang Li ◽  
Jian Jun Yan ◽  
Hua Quan Yang
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Hydration Degree ◽  
Microstructural Characteristics ◽  
Early Hydration ◽  
Cement Pastes ◽  
Curing Conditions ◽  
Microstructure Characteristics ◽  
Micro Morphology

The microstructure characteristics of complex binders under two curing conditions were studied by observing the micro-morphology, analyzing the pore character and means of spectrum test. The results showed that high temperature curing improved the pore structure formed in the early hydration period and reduced the porosity and the coarse pores in pastes. More hydration products were generated on the surface of fly ash particles that made the microstructure of pastes more denser than cured in room temperature. However, high temperature curing had insignificant influence on the CaO/SiO2 ratio of C-S-H gel in pastes and contributed little to the improvement of the later hydration degree and microstrcture of fly ash-cement pastes.

Restricted Hydration of Mass-Cured Concrete Containing Fly Ash

1986 ◽  
Vol 86 ◽  
Author(s):  
R. H. Mills ◽  
N. Buenfeld
Keyword(s):  
Fly Ash ◽  
Relative Humidity ◽  
Portland Cement ◽  
Cement Paste ◽  
Strength Loss ◽  
Surface Strength ◽  
Curing Conditions ◽  
Evaporable Water

ABSTRACTCement paste and concrete specimens containing three different mixtures of portland cement (PC) and high-lime fly ash (FA) were subjected to various curing conditions, and the strengths, non-evaporable water, and porosities were compared with control mixes containing portland cement only. Strength and porosity data indicated that the cementing action of the mixtures was, in all cases, inferior to portland cement. For each mixture the strength loss resulting from imperfect curing, i.e. sealed or exposed to 50% relative humidity, was greater than for portland cement. In the case of concrete drying from one surface, strength differences were found, but these were not as clearly defined as those obtained in the paste specimens.

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