Role of pH on the structure, composition and morphology of C-S-H–PCE nanocomposites and their effect on early strength development of Portland cement

2017 ◽  
Vol 102 ◽  
pp. 90-98 ◽  
Author(s):  
V. Kanchanason ◽  
J. Plank
Keyword(s):  
Portland Cement ◽  
Strength Development ◽  
Early Strength

scholarly journals Effect of Metakaolin on early Strength of GGBS Ternary Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 1551-1557
Author(s):  
Noor Azline Mohd Nasir ◽  
M.J. McCarthy
Keyword(s):  
Adverse Effect ◽  
Portland Cement ◽  
Strength Development ◽  
Replacement Level ◽  
Cement Replacement ◽  
Experimental Programme ◽  
Early Strength

The article reports a laboratory experimental programme that investigated effect of metakaolin on the early strength of concrete made with ternary combinations of Portland cement (CEM I) with ground granulated blast slag (GGBS) and metakaolin (MK). The various level of cement combinations (65%CEM I+30%GGBS+5%MK, 45%CEM I+45%GGBS+10%MK and 45%CEM I+40%GGBS+15%MK) was examined in comparison to CEM I and equivalent GGBS binary concretes for up to 28 days. Results show that the reduction in early strength is greater with the higher cement replacement level. However, the ternary concrete containing 15%MK has minor increase in early strength compared to those with 10%MK but a significant increase in strength is examined at later age (28 days). It is concluded that the presence of MK compensates the adverse effect of GGBS at early strength development and improves the strength at later ages.

scholarly journals Effects of Highly Crystalized Nano C-S-H Particles on Performances of Portland Cement Paste and Its Mechanism

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 816
Author(s):  
Yuli Wang ◽  
Huijuan Lu ◽  
Junjie Wang ◽  
Hang He
Keyword(s):  
Portland Cement ◽  
Cement Paste ◽  
Setting Time ◽  
Tricalcium Silicate ◽  
Strength Development ◽  
Early Age ◽  
Hydration Products ◽  
X Ray ◽  
Early Strength ◽  
Portland Cement Paste

In order to improve the early age strength of ordinary Portland cement-based materials, many early strength agents were applied in different conditions. Different from previous research, the nano calcium silicate hydrate (C-S-H) particles used in this study were synthesized through the chemical reaction of CaO, SiO2, and H2O under 120 °C using the hydrothermal method, and the prepared nano C-S-H particles were highly crystalized. The influences of different amounts of nano C-S-H particles (0%, 0.5%, 1%, 2% and 3% by weight of cement) on the setting time, compressive strength, and hydration heat of cement paste were studied. The hydration products and microstructure of the cement paste with different additions of nano C-S-H particles were investigated through thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffraction (XRD), and scanning electron microscope (SEM) tests. The results show that the nano C-S-H particles could be used as an early strength agent, and the early strength of cement paste can be increased by up to 43% through accelerating the hydration of tricalcium silicate (C3S). However, the addition of more than 2% nano C-S-H particles was unfavorable to the later strength development due to more space being left during the initial accelerated hydration process. It is suggested that the suitable content of the nano C-S-H particles is 0.5%−1% by weight of cement.

scholarly journals Strength development of cement-treated sand using different cement types cured at different temperatures

2018 ◽  
Vol 195 ◽  
pp. 01006
Author(s):  
Lanh Si Ho ◽  
Kenichiro Nakarai ◽  
Kenta Eguchi ◽  
Takashi Sasaki ◽  
Minoru Morioka
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Content ◽  
Bound Water ◽  
Pozzolanic Reaction ◽  
Strength Development ◽  
Different Temperatures ◽  
Early Strength

This study aimed to investigate the strength development of cement-treated sand using different cement types: ordinary Portland cement (OPC), high early strength Portland cement (HPC), and moderate heat Portland cement (MPC) cured at different temperatures. The cementtreated sand specimens were prepared with 8% of cement content and cured under sealed conditions at 20οC and 40οC, and mortar specimens were also prepared for reference. The results showed that the compressive strength of cement-treated sand increased in order of MPC, OPC, and HPC under high curing temperatures. It was interesting that the compressive strength of the specimens using HPC was much larger than that of the specimen using OPC and MPC under 20οC due to the larger amount of chemically bound water. Additionally, it was revealed that under high curing temperatures, the pozzolanic reaction was accelerated in the cement-treated sand; this may be caused by the high proportions of sand in the mixtures.

Early-strength development of portland cement mortars containing air classified fly ashes

1995 ◽  
Vol 25 (2) ◽  
pp. 449-456 ◽  
Author(s):  
J. Payá ◽  
J. Monzó ◽  
E. Peris-Mora ◽  
M.V. Borrachero ◽  
R. Tercero ◽  
...  
Keyword(s):  
Portland Cement ◽  
Strength Development ◽  
Fly Ashes ◽  
Cement Mortars ◽  
Early Strength

scholarly journals The Effects of Fineness and TEA-Based Chemical Admixture on Early Strength Development of Concrete in Construction Site Applications

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2027
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee ◽  
Hyeonggil Choi ◽  
Dong-Eun Lee
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Concrete Strength ◽  
Raw Material ◽  
Strength Development ◽  
Type I ◽  
Chemical Admixtures ◽  
Chemical Admixture ◽  
Early Strength ◽  
Time Required

This study examines effects of cement fineness and chemical admixtures of early strength agents on the early strength development of concrete. Three cement types were selected, namely ASTM type-I ordinary Portland cement (OPC), fineness ordinary Portland cement (FOPC), and ASTM type-III early Portland cement (EPC), and the mixing proportions of concrete were set by adding a triethanolamine-based chemical admixture to FOPC. The evaluation items considered in this study included raw material analysis, compressive strength, and maturity (D∙h). The time required for the development of concrete strength of 5 MPa in the three cement types was estimated and compared. The results revealed that using FOPC enhances the strength development of concrete owing to its higher fineness and SO3 content compared to OPC. In addition, it has been observed that using both FOPC and TCA yields a similar performance to that observed using EPC, in light of the improved early strength development at low temperatures.

scholarly journals The Role of Various Powders during the Hydration Process of Cement-Based Materials

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Shuhua Liu ◽  
Hongling Wang ◽  
Jianpeng Wei
Keyword(s):  
Early Stage ◽  
Steel Slag ◽  
Pozzolanic Reaction ◽  
Hydration Process ◽  
Limestone Powder ◽  
Strength Development ◽  
Early Hydration ◽  
Cement Based Materials ◽  
Early Strength

The role of various powders including glass powder (GP), limestone powder (LP), and steel slag powder (SSP) during the hydration process of cement-based materials was investigated by using X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and strength tests. GP has adverse impact on early strength, but the pozzolanic reaction at later stage enhances the strength development greatly. LP can significantly improve early strength. SSP has a good contribution to the early and later strength of the paste when its content is less than 15%. GP has little effect on the kind of hydration products but relatively large effects on the quantity. Calcium hydroxide (CH) content of GP paste decreases over curing age gradually, which is different from pure cement paste because its pozzolanic activity consumes more CH than that generated from the cement hydration. SSP and LP mainly play a role of filling effect at early stage. Nucleating effect of LP also promotes the early hydration of cement. The hydration of LP occurs at later stage and forms the calcium carboaluminate hydrates. The hydration of SSP is relatively slow, which generates CH at later stage and is effective in the strength development.

scholarly journals Improving Marine Concrete Performance Based on Multiple Criteria Using Early Portland Cement and Chemical Superplasticizer Admixture

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4903
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee ◽  
Jaewook Jeong ◽  
Jaemin Jeong
Keyword(s):  
Portland Cement ◽  
Concrete Strength ◽  
Strength Development ◽  
Construction Productivity ◽  
Concrete Mix Design ◽  
Granulated Blast Furnace Slag ◽  
Chloride Resistance ◽  
Combined Use ◽  
Concrete Mix ◽  
Early Strength

This study sought to examine the performance design of concrete mix proportions to ensure chloride resistance and early strength with respect to C35 (35 MPa), which is the minimum compressive strength class of concrete used in a marine environment. For the proposed concrete mixture, C24 (24 MPa) was selected and binders for concrete were manufactured using a blend of OPC (ordinary Portland cement), EPC (early Portland cement), and GGBS (ground granulated blast-furnace slag). The results of the experiment confirmed that the combined use of EPC and GGBS greatly improve the early-strength development and chloride resistance of concrete. An analysis revealed that the time for removal of forms can be reduced by 5–9 h from the aspect of early concrete strength. Moreover, in terms of construction productivity, EPC and GGBS were reduced by up to 16.39 h/cycle compared to other concretes. Regarding economic and environmental impacts, EPC and GGBS were more effective than C35 concrete. This study is significant as its findings help make it possible to examine the most economical concrete mix design in relation to strength development according to the application of EPC, GGBS, and PC-based admixtures.

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