Spread is better: An investigation of the mini-slump test

Gao, Jinglong; Fourie, Andy

doi:10.1016/j.mineng.2014.11.001

Cited by 49 publications

(22 citation statements)

References 12 publications

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“…Each test was performed using a poly(tetrafluoroethene) mini-slump cone on a flat sheet of poly(methyl methacrylate) marked with grid squares of 2 9 2 cm 2 . Freshly mixed paste was immediately poured into the cone, and then the cone was lifted as slowly as possible (\ 0.005 m/s [23]) to minimise inertial effects. After 1 min, a digital photograph was taken from directly above the resultant pat of material, from which the slump area was calculated using the ImageJ software, calibrated using the scaled grid.…”

Section: Materials Characterisation and MIX Designsmentioning

confidence: 99%

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

2017

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The mini-slump test is a fast, inexpensive and widely adopted method for evaluating the workability of fresh cementitious pastes. However, this method lacks a standardised procedure for its experimental implementation, which is crucial to guarantee reproducibility and reliability of the test results. This study investigates and proposes a guideline procedure for mini-slump testing, focusing on the influence of key experimental (mixing and testing) parameters on the statistical performance of the results. The importance of preparation of always testing at the same time after mixing, testing each batch once rather than conducting multiple tests on a single batch of material, is highlighted. A set of alkali-activated fly ash-slag pastes, spanning from 1 to 75 Pa yield stresses, were used to validate the test method, by comparison of calculated yield stresses with the results obtained using a conventional vane viscometer. The proposed experimental procedure for mini-slump testing produces highly reproducible results, and the yield stress calculated from mini-slump values correlate very well with those measured by viscometer, in the case of fresh paste of pure shear flow. Mini-slump testing is a reliable method that can be utilised for the assessment of workability of cements.

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Section: Materials Characterisation and MIX Designsmentioning

confidence: 99%

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

2017

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“…The slump test was originally developed to determine the "workability" or "consistency" of fresh concrete, and the standard slump instrument is a tapered cylinder with a height of 30 cm, an upper diameter of 10 cm, and a bottom diameter of 20 cm [22]. The slurry was poured into the slump instrument and tamped.…”

Section: Slump Testsmentioning

confidence: 99%

CFD Simulation of Pipeline Transport Properties of Mine Tailings Three-Phase Foam Slurry Backfill

et al. 2017

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A three-dimensional backfill pipeline transport model is developed using the computational fluid dynamics (CFD) technique, which is applied to study the pipeline transport properties of three-phase foam slurry backfill (TFSB). Based on rheological property tests and CFD simulations, the foam phase, pressure, and velocity in the pipeline system are investigated using the CFD mixture method for different bubble volume fractions and bubble diameters. The simulation results indicate that TFSB can maintain a steady state during pipeline transport, experience a markedly reduced pipeline transport resistance, and exhibit better liquidity than conventional cement slurry. Furthermore, as the bubble volume fraction increases, the resistance of the pipeline decreases and the fluidity improves. By contrast, the bubble diameter has little effect on the transport properties of TFSB. The combined results of CFD simulations, slump tests, and strength tests indicate that, when the bubble volume fraction is 15-20 vol %, TFSB can satisfy the necessary strength requirements and exhibit self-flowing transport. The CFD technique provides an intuitive and accurate basis for pipeline transport research and has the potential for wider application in studies of mine backfill.

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“…Time to flow, for instance, from the Marsh cone test is related to apparent viscosity when modeled with cement's characteristics. The minislump spread is related to yield stress (BANFILL, 2006;GAO;FOURIE, 2015). These are techniques of fast execution and rapid implementation techniques, yet both need proper mixing methods to be repetitive.…”

Section: Introductionmentioning

confidence: 99%

Effect of mixing method on the mini-slump spread of Portland cement pastes

Raucci

Cecel

Romano

et al. 2018

Rev. IBRACON Estrut. Mater.

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ResumoThe current compressive strength test for cement classification is performed under a fixed water to cement ratio according to the Brazilian and European standards, regardless the consistency obtained. However, under practical conditions the amount of water required is related to the rheological need to obtain and maintain a desired workability. Intrinsic cement characteristics influence the water demand such as the cement particle's granulometry, specific surface area, density, the presence or not of water reducing admixtures, chemical and mineralogical nature of raw materials, etc., influence particles agglomeration state. Because water demand influences the mechanical properties of cement based products, the compressive strength class under a fixed water to solids ratio specified by the standards may not be representative for the user. The present work investigates the influence of mixing conditions on mini-slump spread results, a test that has been used for many years but never standardized. Cement paste samples were produced with varied mixing conditions (time and rotation speed) using a conventional stirrer and subjected to mini-slump spread test immediately after mixing and at fixed hydration times. Results show that mixing and hydration time do influence on minislump spread. At lower rotation speeds, results variability increases. Under fixed time after first contact with water, increasing rotation speed leads in a reduction of results variability and increase the test's repeatability on cement pastes. Keywords:Portland cement, mini-slump spread, mixing.O ensaio de resistência do cimento, segundo às normas brasileiras e europeia atuais, é realizado com uma relação água/cimento fixa em massa, independente da consistência obtida. No entanto em condições normais de uso, a quantidade de água é uma variável definida com a finalidade de manutenção da consistência dos materiais cimentícios para obter trabalhabilidade adequada. Características intrínsecas dos ligantes, como distribuição de tamanho de partículas, área superficial especifica, densidade e natureza química ou mineralógica, ou extrínsecas, como presença de aditivos, temperatura ambiente e da água, tempo e energia de processamento, etc., podem afetar de forma distinta o estado de aglomeração e, consequentemente, a necessidade de líquido para a mistura. Como a demanda de água influencia a resistência mecânica dos produtos, a utilização da relação água/cimento fixa torna, em termos práticos, a classificação do cimento pela resistência pouco significativa para o usuário. Neste trabalho foi investigada a influência das condições de mistura na repetibilidade do ensaio de mini-slump, bastante usado para avaliação da quantidade de água nas composições, mas não normatizado. Pastas de uma mesma amostra de cimento foram misturadas por diferentes tempos e/ou rotações, usando um agitador mecânico convencional, e submetidas ao ensaio de mini-slump imediatamente após o ensaio ou após o mesmo tempo de contato com a água. Observou-se influência signific...

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Spread is better: An investigation of the mini-slump test

Cited by 49 publications

References 12 publications

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

CFD Simulation of Pipeline Transport Properties of Mine Tailings Three-Phase Foam Slurry Backfill

Effect of mixing method on the mini-slump spread of Portland cement pastes

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