The development of a new method for the proportioning of high-performance concrete mixtures (original) (raw)
Mix Design of High Performance Concrete Using Silica Fume and Superplasticizer
High Performance Concrete (HPC) now a days used widely in the construction industry world wide. To produce HPC with normal ingradients we use mineral admixtures like Silica fume, fly ash and metakoline and workable agents Superplasticizers are also used. The usage of mineral admixtures in the concrete not only enhances its strength properties but also durability. The compressive strength are investigating finding the optimum use of mineral admixture(Silica fume of levels 0, 5, 10,15, 20 and 25% at 7 days and 28 days of curing). The present investigation aims to give design mix for HPC by using silica fume and superplasticizers.
Properties of Ultra High Performance Concrete Containing Superfine Cement and without Silica Fume
Journal of Advanced Concrete Technology, 2014
To avoid the disadvantages caused by using silica fume, by using superfine cement (SC) to substitute silica fume, a new kind of ultra high performance concrete (SC-UHPC) was prepared and introduced. The influence of component types and dosages on the mechanical properties of SC-UHPC was investigated. The results show that 40% ground granulated blast furnace slag (GGBFS) or 10% fly ash (FA) & 30% GGBFS replacing SC are the most appropriate proportions to get high strength with satisfied workability and low cost. A suitable amount of defoaming agent (DA) in superplasticizer (SP) effectively reduced the void ratio in the UHPC. To optimize the strength and fluidity, the rational natural sand distribution with lowest clay particles amount can be used. The small sized steel fibers added into the mixture effectively improved the flexural behavior of SC-UHPC. Multiple nonlinear analysis show that, with sufficient calcium silicate hydrate (C-S-H gel) and enough mixture fluidity, the compressive strength of UHPC is closely related to the water to binder ratio and void ratio, and increases linearly with the incremental fiber amount. Microstructure analysis proved that the microstructure of SC-UHPC has ultra high density and homogeneity.
Neutron
In this research, a lightweight concrete mixture was made with foam and made use of the remaining broken rock from the Crusher Machine process, which was washed ashes. Other added ingredients used in the mixture are Silica Fume, Superplasticizer (Admixture Type F) and Bonding. This reseach uses a mix design from Circular Letter Number: 44 / SE / M / 2015 Concerning Design Guidelines for Mixing Light Material with Foam Mortar for Road Construction, Ministry of PUPR. Trial mix variations carried out are in proportion (SF 5%; BO 0.5%), (SF 10%; BO 0.5%), (SF 5%; BO 1%), (SF 10%; BO 1% ), as well as foam agents with variations 1:20 and 1:40. The treatment process (curing) of the test object is immersed in a water bath, and the testing of the compressive strength of the test object is carried out at the age of 7 days, 14 days and 28 days. By using stone ash, lightweight concrete was obtained with an average specific gravity of 1722 kg / m3 to 1884 kg / m3. From the research results obtai...
Effect of Silica Fume on High Performance Concrete Strength
High Performance Concrete (HPC) is now a days used widely in the construction industry worldwide. To produce HPC with normal ingredients one use mineral admixtures like silica fume, fly ash and metakoline. In addition admixtures including Superplasticisers are also used. This paper investigates the effect of silica fume (SF), added in varying percentages (0, 3, 5, 7.5, 10, 12.5%), on concrete strength. Superplasticiser-(Viscocrete Tempo 12)-was added to the concrete mixtures as well. Compressive strength, shear strength and tensile strength tests were conducted, and the results were discussed. Results showed that the compressive strength changes with the varying percentage addition of silica fume. The highest compressive strength (88 MPa) was obtained when the percentage of silica fume was 7.5 % of the cement weight. Beyond 7.5 % silica fume, the compressive strength started descending. Tensile and shear strength were found to vary in an inverse relationship with the increasing percentage of silica fume. A significant reduction in tensile strength and shear strength were recorded when the silica fume percentage is increased. However, the 10% ratio between tensile and compressive strength for normal concrete, was not found to be, relevant for HPC with SF.
Cement and Concrete Research, 2019
High silica fume content used in ultra-high performance concrete (UHPC) can increase viscosity and render agglomeration issue, leading to reduction in mechanical properties, including bond to fibers. This study investigates the effect of silica fume content, ranging from 0 to 25%, by mass of cementitious materials, on rheological, fiber-matrix bond, and mechanical properties of non-fibrous UHPC matrix and UHPC made with 2% micro-steel fibers. Binary mixtures consisting of cement and silica fume with targeted mini-slump flow were specifically prepared. The involved mechanical properties include compressive, flexural, and tensile behavior. Rheology, fiber-matrix bond, flexural, and tensile strengths of UHPC were linked to each other using fiber dispersion and orientation analyses or the Composite Theory. Test results showed that UHPC made with 10% to 15% silica fume obtained the highest fiber-matrix bond, flexural, and tensile properties. Such silica fume content was found to result in lower viscosity and more uniformly distributed fibers as determined by image analysis. The flexural and tensile strengths of UHPC made with 5%-20% silica fume can be effectively predicted using the Composite Theory considering obtained fundamental inputs, such as flexural or tensile strengths of matrix, fiber characteristics, and fiber-matrix bond strength. The experimental-to-predicted tensile and flexural strength ratios were in the range from 0.9 to 1.1. However, the predicted strengths of UHPC mixtures with 0 and 25% silica fume were greatly lower than the experimental values due to high viscosity and low packing density.
Advances in materials research, 2018
In the present study, a special attention has been paid to the effects regarding the use of different superplasticizers in different dosages. To do so, 36 mixes of normal and self-compacting concrete with two water/binder ratios of 0.35 and 0.45, four different types of superplasticizer including melamine-formaldehyde, naphthalene-formaldehyde, carboxylic-ether and poly-carboxylate, four different superplasticizer/cement ratios of 0.4%, 0.8%, 1.2% and 1.6% and two silica fume/cement ratios of 0% and 10% have been cast. Moreover, the initial and final setting time of the pastes have been tested. For self-compacting mixes, flow time, slump flow, V-funnel, J-ring and L-box tests have been carried out as well as testing the compressive strength and rupture modulus. For normal concrete mixes, slump test has been conducted to assess the workability of the mix and then for each mix, the compressive strength and rupture modulus have been determined. The results indicate that in addition to ...
Development of high performance concrete using silica fume at relatively high water–binder ratios
Cement and Concrete Research, 2000
The aim of this study was to investigate the possibility of developing high performance concrete (HPC) using silica fume (SF) at relatively high water ± binder ratios. For this purpose, water ± binder ratios of 0.45 and 0.50 were considered. Test specimens were air and water cured and exposed to a medium temperature range of 20°C to 50°C. The compressive strength, modulus of elasticity and initial surface absorption (ISA) of hardened concrete were determined in the laboratory. Test results indicated that concrete under water curing offers the best results. The highest level of compressive strength and modulus of elasticity and the lowest level of ISA were produced by SF concrete under water curing and at temperature of 35°C. Data collected also revealed that, under controlled curing conditions, it is possible to produce HPC at relatively high water ± binder ratios. D
Production of High-Performance Silica Fume Concrete
American Journal of Applied Sciences, 2017
This research aimed to produce concrete that will decrease disadvantages of portland concrete and resolve it. Mixture of Silica fume with concrete in this paper shows that the strength and hardness are increased. In this research the main gools is to compare the deference of compressive strength between standred concrete and concrete with silica fume with different additives ratio and to explore its effect on the main physical properiets of concrete. To achieve our goals in this research about 180 samples prepared to examened it's compressive strength, all concrete sample has the same mixing ratio and distributing to standard and Silica fume added by the volume (5, 10, 15, 20 and 30%). The results show that the recommended addition was 15% of Silica fumes for optimum compressive strength that reaches 74.8 MPa. Also the economy of mixture compare to the market prices makes silica excellent to use as addition filler to concrete.
EXPERIMENTAL STUDY ON BEHAVIOR OF HIGH STRENGTH CONCRETE WITH SILICA FUME AS AN ADMIXTURE
This experiment is directed towards developing a better understanding on the isolated contribution of silica fume on the compressive strengths of high-strength concrete (HSC). Extensive experimentation was carried out over water–binder ratio as 0.26, silica fume ranges from 0 to 25%. For all the mixes, compressive, and split tensile strengths were determined at 28 days. The compressive, as well as the tensile, strengths increased with silica fume incorporation, and the results indicate that the optimum replacement percentage is not a constant one but depends on the water– cementitious material (w/cm) ratio of the mix. The main objective of the present investigation is to study the behavior of high strength reinforced concrete beams (replacement of cement with silica fume). Super plasticizer is used to achieve require workability. Keywords: High strength Concrete, Compressive strength, Split tensile strength, Silica fume.
Concrete is the most extensively used in large-scale constructions where strength, workability, and durability are main requirements. Engineers are continually pushing the limits upward to improve its performance with the help of innovative chemical admixtures and supplementary cementitious materials. Nowadays, most concrete mixtures contain supplementary cementitious material which forms part of the cementitious component. The main benefits of SCMs are their ability to replace certain amount of cement and still able to display cementitious property, thus reducing the cost of using Portland cement. This paper investigated the properties of concrete by partial replacement of cement with 5, 10, 15% and 20% of silica fume by weight. Compressive strength of concrete specimens, were compared with concrete specimens, with no silica fume, at 7, 14, 28, 56 and 90 day’s age. A constant water cement ratio of 0.35 was maintained and to compensate its workability, super-plasticizer was used. Specimens which included both 6 inches diameter cylinders and 4 inches cubes were casted and tested in accordance to ASTM standards. Test results indicated improvement, in the compressive strength properties of cube samples by the inclusion of silica fume as a partial replacement of cement at a replacement level of 10% but showed totally opposite behavior in case of cylinders.