Papers by Keyword: Mix Proportion

Abstract: Self-compacting steel fiber concrete must meet the strength standard after steel fiber is added and must have good fluidity. The test results show that the addition of steel fiber to concrete will affect the fluidity of concrete. Compared with ordinary concrete, the addition of steel fiber will improve the compressive strength and flexural tensile strength of concrete to varying degrees. The mix proportion test can be carried out in stages, i.e. the mix proportion meeting all performance indexes used is determined first, then steel fiber is added and adjusted to determine the best mix proportion.

Abstract: Steel fiber reinforced concrete (SFRC) is developed traditionally from ordinary concreteadmixed with randomly distributed steel fibers. The matrix of SFRC is always formed by adjustingthe mix proportion used for the ordinary concrete, which plays the role of controlling the properties ofSFRC. In this paper, the mix proportion of self-compacting concrete (SCC) compared with vibrationcompacted concrete (VCC) is statistically analyzed. A predictive formula for water-binder ratio isproposed in relation to the designed compressive strength of SCC and the cement strength affected bymineral admixtures. It is expected to provide reference for the mix proportion design for flowing andhigh-flowing SFRC.

Abstract: To produce effective cement paste backfill materials at iron mines technologically and economically, orthogonal experiments of mix proportions with extra-fine unclassified tailings were carried out. The results of the range analysis showed that the sensitivity of influential factors to the slurry slump is sequentially mass concentration, tailing/rock ratio, and cement/(tailing+rock) ratio. The sensitivity to bleeding rate, concretion time and 28-day uniaxial compressive strength is sequentially mass concentration, cement/(tailing+rock) ratio and tailing/rock ratio. Relationships of paste properties and influential factors can be demonstrated with regression analysis. Additionally, the optimal mix proportion for cement paste backfill was obtained with 78% mass concentration, 7:3 tailing/rock ratio and 1:25 cement/(tailing+rock) ratio. The slump, bleeding rate, concretion time and R28 of the optimal mixture are 25.2 cm, 8.77%, 20.9 h and 1.29 MPa, respectively. The experimental results show a feasible way to produce the industry standard backfilling materials.

Abstract: Mortarless interlocking blocks have the advantage of convenient construction and low cost, but establishing the geometry interlocking mechanism between horizontal blocks has been overlooked. Optimizing the shape of mortarless interlocking block. The connection of vertical direction in the form of a frustum of a cone, and the connection of horizontal direction in the form of trapezoid shape. This design proposal builds geometry interlocking mechanism between the block and its all adjacent ones. Setting cone and rectangular holes on block body, accordingly, block laying could forming taper vertical channel and rectangular vertical channel. The concrete of interlocking mortarless block has particularity, which is not suitable for “Mix Proportion Design of Ordinary Concrete Regulation” (JGJ55-2010) of China. This paper presents a platter idea to establish the concrete mix proportion design method of mortarless interlocking block, moreover, an example calculation and confirmatory experiment is dispensable.

Abstract: Oil palm waste materials which consist of palm oil fuel ash (POFA) and oil palm shell (OPS) are contributing negatively towards the environment as they are normally disposed in landfills. In recent years, research studies found that POFA and OPS can be used as potential replacements for cement and coarse aggregates respectively in the effort to solve the environmental problems contributed by these wastes. In this study, POFA was used to replace ordinary Portland cement at 15% by weight of binder while OPS fully replaced the coarse aggregates to produce lightweight concrete. A suitable mix proportion for OPS concrete was determined through several trial mixes and then cement was partially replaced by POFA to produce POFA OPS concrete. The POFA OPS concrete registered density of 1870 kg/m³ which categorises it as a lightweight concrete. This concrete also produced slump value of 100 mm and compressive strength of 25.50 and 30.50 MPa at age 7 and 28 days respectively.

Abstract: Oil palm shell (OPS) is a renewable resource obtained from agricultural solid waste after the extraction of palm oil. It has been previously reported that OPS can be used as a coarse aggregate substitute in the manufacture of structural lightweight concrete. Since OPS is an organic material, its properties may degrade after a certain period of time unless pre-treatment is applied on the aggregates. Polyvinyl alcohol (PVA) can be used to treat the OPS before being incorporated as coarse aggregates in concrete. It has been determined that the use of PVA as pre-treatment enables an improvement to the properties of raw OPS aggregates and consequently the resulting concrete. In this research work, the effect of PVA as pre-treatment on OPS aggregates on the mix proportion of OPS concrete was investigated. The results show that there was an increase in the slump values of the OPS concrete made with PVA treated OPS aggregates. The 28-day air-dry density and compressive strength of PVA treated OPS concrete slightly increased as compared to raw OPS concrete.

Abstract: Analyze the influence factors of mix proportion affecting concrete freeze-thaw damage. Use the five main performance indexes of the concrete, which are compressive strength, strength of extension, impermeability grade, and frost resistance grade and per unit volume cost concrete, as the objective function of multi-objective optimization equation. Invoke the fgoalattain function in the MATLAB Optimization Toolbox to solve. The optimized parameters of mix proportion of frost resistance construction of unit concrete in cold region are: concrete 1532.6kg, water 910kg, sand 5510.6kg, 5-20mm cobblestone 3747.2kg、20-40mm cobblestone 3658.6kg、40-80mm cobblestone 4733.5kg、80-150mm cobblestone 4738.1kg, and the dosage of water reducing agent is 7.3kg.

Abstract: The effective treatment of void cement concrete pavement slab through grouting technology is the important premise of ensuring the service performance of asphalt overlay engineer on cement concrete pavement. Based on the current problems of grouting technology, we did experimental studies on the mixing proportion of grout slurry and analyzed the effects of slurry composition and admixture type on mechanical properties including the strength, mobility, viscosity, expansion rate and bleeding rate of the slurry and on the service performance. Based on these, we put forward the control indexes for grouting slurry mix proportion determination which provided guidance for the design and construction quality control of grouting under the old cement concrete pavement slab.

Abstract: Red mud foam lightweight thermal insulation material was prepared by red mud, fly ash, cement as main raw materials, adding a certain amount of adhesive, through ingredients, mixing, molding, foam, sintering process. The influence of the ratio of red mud and fly ash on the properties of materials was studied and the mechanism of influence was analyzed. The test results show that performances of the samples were best when the ratio of red mud and fly ash is 5:4 and its flexural strength is 0.44MPa, compressive strength is 1.23MPa, density is 481kg/m³.

Abstract: The foundation backfill materials with pulverized coal ash and admixture gypsum fly ash were studied. The laboratory experiments were designed to determine its compaction characteristics, compressibility, intensity and bearing capacity of foundation with different mixture ratio. Dry density and strength property of fly ash with different water content were analysed. The result shows that the modulus, strength and foundation bearing capacity all have been greatly improved when gypsum was added into fly ash The proper mix proportion of the gypsum fly ash is very suitable for engineering application and this research provides a scientific reference for the similar projects.