Concrete Science

Ramachandran, V.; Feldman, R.F.

doi:10.1016/b978-081551373-5.50005-2

Cited by 74 publications

(92 citation statements)

References 56 publications

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“…That was mainly due to the high activation effect of the hyperbranched polyesteramides at later stages and to the decrease of the apparent porosity which resulted from further increase of the hydration products. 36 Furthermore, the dispersing effect 30,31 as revealed by SEM of the hyperbranched polymers/cement pastes indicated improvement in the workability of such pastes and hence an enhancement of the compressive strength was obtained. 34 The compressive strength of HBPA 2 was slightly higher with OPC and PLC than that with respect to HBPA 1 particularly with 5% concentration.…”

Section: Figurementioning

confidence: 92%

“…Thus, as mentioned in the literature, it was concluded that this polymer acted as plasticizer and/or superplasticizer where the plasticizers were generally defined as the special category of water-reducing agents which allows much greater water reduction or alternatively extreme workability of the concrete without undesirable side effects such as excessive air entrainment or set retardation. 30,31 On the other hand, HBPA 1 and HBPA 2 increased setting times (initial and final) of either OPC or PLC (Table II). Initial setting time increased in case of 5% HBPA 1 from 130 to 150 min with OPC and from 60 to 80 min with PLC.…”

Section: Figurementioning

confidence: 93%

“…Hence, electrostatic repulsion is generated between the cement particles reducing the interparticle attraction and preventing flocculation or agglomeration where well-dispersed system is obtained. 30,31 That fact leads to better properties of the formed cement pastes such as better hydration by using less water to penetrate between the particles where the combined water content is the main indication for better hydration. Hence, the amount of hydration products is increased by the deposited polymers in the pore spaces of the hardened cement pastes, in addition to the formed polymer film which fills up the pores of the cement pastes.…”

Section: Introductionmentioning

confidence: 98%

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Employing of some hyperbranched polyesteramides as new polymeric admixtures for cement

Amin

Darweesh

Ramadan

et al. 2011

J of Applied Polymer Sci

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Hyperbranched polyesteramides (HBPA 1 and HBPA 2 ) were synthesized by the bulk polycondensation of maleic anhydride (MA n ) as an A 2 monomer with both of diisopropanolamine (DIPA) and diethanolamine (DEA), respectively, as B 0 B 2 monomer. The prepared polymers were analyzed with IR, GPC, 1 H NMR, TGA, and DSC. The hyperbranched polyesteramides were applied as polymeric admixtures in two different types of cement, namely ordinary Portland cement (OPC) and Portland limestone cement (PLC). Several parameters were studied to evaluate the action of HBPA 1 and HBPA 2 polymers as cement admixtures. Adding HBPA 1 and HBPA 2 decreased the water of consistency and increased the compressive strength with no effect on the chemical composition of the cement phases. The combined water content and bulk density displayed the same trend as compressive strength. The IR spectra of the formed phases for the mixed cement pastes with HBPA 1 and HBPA 2 illustrated increased intensities of the absorption bands than those of the pristine cement pastes. The SEM photos showed that the incorporation of HBPA 1 and HBPA 2 in cement phases affected the morphology and microstructure of the formed hydrates.

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Section: Figurementioning

confidence: 92%

Section: Figurementioning

confidence: 93%

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Employing of some hyperbranched polyesteramides as new polymeric admixtures for cement

Amin

Darweesh

Ramadan

et al. 2011

J of Applied Polymer Sci

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“…Fibers have mainly two types: metallic and non-metallic. Steel is the main source for the first type; whereas natural fibers (vegetal type) represent a main and cheap source of the second type (Parret, 1972;Ramachandran, 1981). A continuous research oriented towards the evaluation of material (pure and composite) properties is the direct way to identify the efficiency of local resources of material.…”

Section: Introductionmentioning

confidence: 99%

Simulation and prediction for the effect of natural and steel fibers on the performance of concrete using experimental analyses and artificial neural networks numerical modeling

Hodhod

Abdeen

2011

KSCE J Civ Eng

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Utilization of fibers as concrete reinforcement is one method of preserving environment through the recycling of agriculture and industrial wastes. However, the optimum and efficient application of these fibers requires a measurable evaluation of their effect on properties and performance of concrete. In this study, the application of metallic steel fibers and natural (Linen) fibers in concrete industry is investigated, experimentally. Twenty one mixes are made with different mix proportions and with different types of fibers. The parameters are concrete characteristic strength, age and type of reinforcing fibers. Compressive, tensile and impact strength were measured for all mixes in addition to the residual compressive strength after exposure to elevated temperature. Measurements were also made using two Non Destructive Testing (NDT) techniques. Experimental results were compared and showed the enhancement level obtained by including steel and natural fibers. Following this experimental effort, one of the artificial intelligence techniques (Artificial Neural Network) was applied for simulating and predicting the performance of concrete with different mix proportions. The current paper introduced the Artificial Neural Network (ANN) technique to investigate the effect of natural and steel fibers on the performance of concrete. The results of this study showed that the ANN method with less effort was very efficiently capable of simulating and predicting the performance of concrete with different mix proportions and different types of fibers.

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“…To reduce the consumption of cement and seal of the concrete structure as a finely dispersed mineral additives in concrete mixture was introduced metakaolin (table 2). Moreover, the amount should not exceed 15% by weight of cement, as it contains active silicon dioxide, and aluminum oxide in about equal proportions and therefore stronger than microsilica binds free calcium hydroxide, which reduces the alkalinity of the medium in the concrete and can cause corrosion of steel reinforcement [12]. Furthermore, the introduction of metakaolin as any other from fine fillers in more quantity increases water demand of the concrete mix due to its fineness and a large specific surface area values reaching 15 m 2 /g and above [15].…”

mentioning

confidence: 99%

Modified fine-grained concrete for facing and repair of the hydraulic structures

2016

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Abstract. This article is devoted to improve the performance characteristics of plasticized fine-grained concrete for the hydraulic structures. The results of experimental studies on the selection of the optimal dosage of components. Justified the application of plasticized fine hydraulic concrete for facing and repair of the hydraulic structures. The result of the experimental study is the selection of the optimal composition of the fine hydraulic concrete with improved characteristics.The Russian Federation has a large number of rivers with a total length of about 10 million km, many of which are navigable. A large part of the river hydraulic structures due to their intensive use is in poor condition. Repair of such structures are generally very timeconsuming and expensive.To solve the problem of increasing the effective performance of hydraulic fine-grained concretes need to optimize their composition and technology of preparation and use the organic and mineral modifying additives [1][2][3][4][5].The aim of the work was to obtain the fine-grained concrete for facing and repair of river hydraulic structures which has the necessary strength, waterproofness and frost resistance due to seal its structure through the use of the organic and mineral additives in the form of superplasticizer, metakaolin and hydrophobizing silicone fluid. Table 1. Physical and mechanical properties of fine-grained concrete plasticized "Khimkom F-1". Сomposition and propertiesNumber of composition

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Concrete Science

Cited by 74 publications

References 56 publications

Employing of some hyperbranched polyesteramides as new polymeric admixtures for cement

Employing of some hyperbranched polyesteramides as new polymeric admixtures for cement

Simulation and prediction for the effect of natural and steel fibers on the performance of concrete using experimental analyses and artificial neural networks numerical modeling

Modified fine-grained concrete for facing and repair of the hydraulic structures

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