Effect of admixtures on the setting times of high-strength concrete

Brooks, J. J.; Johari, Megat Azmi Megat; Mazloom, Moosa

doi:10.1016/s0958-9465(00)00025-1

Cited by 247 publications

(96 citation statements)

References 9 publications

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“…The prolonged setting times of the cement pastes with starch additions may be attributed to retardation of hydration of some cement compounds such as tricalcium silicate (C 3 S) and tricalcium aluminate (C 3 A) (Ramachandran 1995). According to Brooks et al (2000) it may also be due to adsorption of the admixture onto the cement grain surfaces. It should however, be pointed out that though admixtures may delay setting times in concrete, mechanical properties of the concrete is not negatively affected.…”

Section: Setting Times Testsmentioning

confidence: 99%

Strength and Durability Properties of Concrete with Starch Admixture

Akindahunsi

Uzoegbo

2015

International Journal of Concrete Structures and Materials

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This paper examines some properties of concrete, such as strength, oxygen permeability and sorptivity using starch [cassava (CA) and maize (MS)] as admixtures. Concrete cubes containing different percentages of the CA and MS by weight of cement (0, 0.5, 1.0, 1.5 and 2.0 %) were cast. Compressive strength tests were carried out after 3, 7, 14, 21, 28, 56, 90, 180, 270 and 365 days of curing. Oxygen permeability and sorptivity tests were carried out on another set of concrete specimens with the same percentages of starch at 7, 28, 90, 180, 270 and 365 days. Oxygen permeability and sorptivity tests data obtained were subjected to Kruskal-Wallis one-way analysis of variance by ranks. The strength increase after 1 year over the control for CA 0.5 and CA 1.0 are 2.7 and 3.8 % respectively, while MS 0.5 and MS 1.0 gave 1.5 % increase over control. These results showed a decrease in oxygen permeability and rates of sorptivity, with concretes containing starch as admixtures giving better performance than the control concretes.

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Section: Setting Times Testsmentioning

confidence: 99%

Strength and Durability Properties of Concrete with Starch Admixture

Akindahunsi

Uzoegbo

2015

International Journal of Concrete Structures and Materials

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“…These will help in scheduling the various stages in-volved in concrete construction operations such as transporting, placing, compacting and finishing of concrete. This information is a necessity when deciding whether or not to use a retarding admixture or accelerator (Brooks et al 2000). The setting times of the concrete mixtures were determined in accordance to ASTM C 403 (2008).…”

Section: Setting Time Testmentioning

confidence: 99%

Fresh Properties of Self-Compacting Concrete Containing Ground Waste Glass Microparticles as Cementing Material

Sharifi

Afshoon

Firoozjaie

2015

ACT

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In this study, the fresh properties of self-compacting concrete (SCC) incorporating ground waste glass (GWG) as cementing material were experimentally investigated. GWG was used as a partial replacement for cement at replacement levels of 0, 5, 10, 15, 20, 25 and 30% by weight. Reducing the consumption of cement in construction is a major issue in terms of economic performance. Such reduction would also contribute to the environment by lessening the harmful impact of the manufacturing process. Concrete mixtures containing different levels of GWG were prepared with the water to cementitious materials ratio of 0.51. The examined properties included workability, wet density, air content and setting time. Workability of the fresh concrete was determined by using the slump flow, visual stability index, V-funnel, J-ring, L-box and GTM screen stability tests. The results indicate that there is a slight decrease in the wet density of self-compacting ground waste glass concrete (SCGWGC) of nearly 1.37% with the increase of GWG content. The conclusion is that using GWG significantly increases the workability of SCC mixtures. As the GWG increases, the slump flow also increases at a constant amount of water and super-plasticizer, but the concrete flow time decreases. The results showed that it is possible to successfully produce SCC with GWG as cement replacement.

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“…The hydration of cement and cement compounds, particularly tricalcium silicate (C 3 S) which is responsible for the early strength of cementitious materials, was retarded due to lower amount of cement available in PFA and GGBS pastes. The setting of cement paste has been postulated to result from two fundamental steps: coagulation establishing contacts between cementitious grains and the formation of hydrates in the contact zones making the coagulation structure rigid (Brooks et al 2000). For a binder with high cement content, the cement particles are expected to be more closely packed which could result in greater interparticle contact and thus could speed up setting.…”

Section: Setting Timesmentioning

confidence: 99%

Effects of PFA and GGBS on Early-Ages Engineering Properties of Portland Cement Systems

Zhou

Slater

Wavell

et al. 2012

ACT

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A comprehensive study is presented on the effects of pulverised fly ash (PFA) and ground granulated blast furnace slag (GGBS) on early-age engineering properties of Portland cement (PC) systems. It has been found that partially replacing PC by PFA or GGBS resulted in longer setting times but better workability with PFA exhibiting more prominent effect than GGBS. As the replacement level increased, the setting of both PFA and GGBS pastes further delayed but workability of concrete was enhanced. PFA concretes exhibited consistently lower compression and splitting tensile strengths than PC ones. As the replacement level increased, strengths decreased. At the replacement level up to 30% by mass, GGBS concrete exhibited higher splitting tensile strength than PC concrete. However, as the replacement level further increased, it developed lower strength than PC concrete up to 21 days. Then, it managed to gain higher splitting tensile strength than PC concrete at the replacement levels up to 70% by mass at 28 days. Both PFA and GGBS can reduce drying shrinkage and the reduction effects became more significant as replacement level increased with GGBS performing better than PFA. Adding fibres into PFA concrete increased its splitting tensile strength and further reduced its drying shrinkage.

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Effect of admixtures on the setting times of high-strength concrete

Cited by 247 publications

References 9 publications

Strength and Durability Properties of Concrete with Starch Admixture

Strength and Durability Properties of Concrete with Starch Admixture

Fresh Properties of Self-Compacting Concrete Containing Ground Waste Glass Microparticles as Cementing Material

Effects of PFA and GGBS on Early-Ages Engineering Properties of Portland Cement Systems

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