Mechanical Properties of colored concrete
2.6.1 Fresh properties of colored concrete
A) Fluidity of cement mortar
Hyun-SooLeea, et al. studied effects of inorganic pigments on the fluidity of cement mortar. The most commonly used in concrete products two types of pigment were used: The first was a Korean product pigment (A) and the second was a German product pigment (Z). The main ingredient of red, yellow, and black pigments is iron oxide (Fe2O3) and that of the green pigment is chrome oxide (Cr2O3). Eighteen mortar specimens for each mixture were prepared, and experiments were carried out. The results were, The German product pigment was smaller than the Korean product. In terms of water soluble and main ingredients, the Korean product
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The production and processing technology of high-quality pigments must be studied more extensively. When the mixing ratio of the red pigment (P/C) RA was changed from 3% to 12%, the flow of the red mortar decreased by 8 mm to 39 mm, respectively, and when the red pigment RZ was used, the flow of the red mortar RZ decreased by 11 mm to 40 mm compared with the standard flow of 210 mm. If the pigment mixing ratio exceeded 9%, flow value decreased to 26 – 58 mm from the standard flow. Accordingly, the acceptable mixing ratio of the red pigment must be below 9% to obtain fluidity over a flow of 180 mm, considering its workability at the site. When the yellow pigment was mixed with the cement mortar, the pigment decreased the fluidity of the mortar because it contained needle-shaped particles. If the mixing ratio of the yellow pigment exceeded 6%, the flow of the yellow mortar may decrease to 180 mm, as well as the fluidity of the mortar, adversely affecting workability. In this regard, the proper mixing ratio should be below 6%. In the case where the green or black pigment BZ was mixed with the cement mortar, a flow decrease as the result of mixing of the pigments does not need to be considered because there was almost no …show more content…
studied the advantages of using a mortar-based mix design methodology for C-SCC. Many mortars and colored SCC were prepared including different pigments shape and fineness. Synthetic pigments are extensively used as color agents in cement based materials (Ordinary ‘‘grey” Portland cement (G) or white Portland cement), their requirements are included in many sources (Bower et al, 1964 and Buehrer et al, 1987) [28-29]. Three iron oxides yellow (y), red (r), black (b), carbon black (c) and two copper phthalocyanines blue (phg) and green (phg) were used. Some pigments can strongly increase air incorporation in fresh concrete, as in the case of the cupric phthalocyanines (Barragan B.E. et al, 2008) [30]. Mortar tests are also effective to detect this fact. It can be seen a significant increase in air content appears when phthalocyanine pigments were used; as a consequence notable reductions in strength must be expected
HYPOTHESIS: My hypothesis is that none of the Crayola colors are pure colors because they are a mixture of other color components.
Self-compacting concrete (SCC), also known as self-consolidating concrete, is a specialized high performance concrete that does not need to be compacted by vibration as it compacts into every corner and space of a formwork as a result of its own weight. The most laudable property of SCC is that it leaves no void in the formwork, and that too, without the need of mechanical vibration (De Schutter, 2007; Okamura & Ouchi, 2003; Hurd, 2002). SCC, therefore, has superior engineering properties that make it a highly versatile and immensely useful material for construction. It was first developed in Japan in 1988 as a result of research on durability of concrete structures. Since then, research on SCC has progressed to a large extent, leading to its increased applicability in the construction industry.
The result for density of all mixtures with difference proportions of pure copper slag and spent copper slag shown in Table VIII and Table IX respectively. The density of cement-sand brick slightly increased as spent copper slag content was increased. The density of cement-sand brick was increased by almost 13.4% for mixture of replacement 60%PCS as fine aggregates, due to the fact that pure copper slag has higher specific gravity compared to the river sand.
Ordinary Portland cement (C 53 grade) conforming to the requirements of IS 12269 (ASTM C 150-85A) was used in the study. Natural river sand was used as fine aggregate and crushed angular granite stone was used as coarse aggregate. Coarse aggregate with combined grading of 50% passing through 20mm sieve and retained on 12.5mm and 50% passing through 12.5mm and retained on 4.75mm sieve conforming to IRC 44 was adopted.
Cement is a finely ground compound of limestone and clay or marl (Chandigarh, 2001). It is used in hydraulic binding since it hardens and binds together aggregates and becomes waterproof thereafter. The most popular use of sand is in building and construction where it is used to bind sand and gravel to obtain concrete used in constructing houses, roads, water channels, among others. Yanbu Cement company produces different types of cement such as Portland cement types I, II, III and IV.
Factor that can influence the strength and durability of concrete are weathering action, chemical attack and any process of deterioration and the main factor influence strength and durability of permeability are can be because of the uses of the admixture of the concrete.
The actual calcium-to-silicon atomic ratio is typically greater than the value of 1.5 represented by C3S2H8 and may vary up to 2 or more. Because of the variable composition this phase is often simply referred to as calcium silicate hydrate or C-S-H. The C-S-H is the principal cementing compound in portland cement concrete and is largely responsible for providing strength and other properties to the concrete. In addition to C-S-H and CH hydrated portland cement contains aluminofer¬rite phases (AFm and AFt) produced by the hydration of the other portland cement clinker compounds, C3A and C4AF, in the presence of
“High Performance Concrete” was defined as a concrete with high durability due to a low water-cement ratio by professor Aitcin et al (Gangneetal 1989). Since then, the term high performance concrete has been used around world to refer to high durability concrete. Therefore, H.Okamura and M.Ouchi, the authors, of an invited paper on SCC for JACT 2003 have changed the term for the proposed concrete, for their work, to “Self – compacting High performance Concrete”.
2.1 Introduction In a traditional way, a concrete mix is designed based on the code requirements and recommendations, which uses the empirical values obtained from previous experiences. Compressive strength of concrete is determined by conducting standard uniaxial compression test on standard cylindrical sample specimens of ages 7 & 28 days, following the standard procedure and test values are reported in accordance with ASTM and ACI standards. If the strength value obtained from the test is less than the required strength after 28 days from date of placing of concrete, the entire process of concrete mix design has to be repeated until the required strength value is achieved, which is time consuming and costly. Numerous test samples with different mix ingredient proportions have to be created to achieve the required strength, and this is an iterative process. So, every mix designer wants a tool or methodology to predict the compressive strength of concrete required at the time of design, before placing the concrete.
studied the properties of pigment dyed concrete interlocking blocks (CIBs). The coloring agents used were synthetic iron oxide pigment and brown iron oxides there were produced from steel manufacturing. Ordinary Portland cement, sand, stone dust and pigment are used to manufacture CIBs. The used iron oxides consisted of brown iron oxide (A) and iron oxide pigment (B). Pigment A, and Pigment B had very little difference in flexural strength. When combining Pigments A and B, a maximum strength was obtained with a mixing ratio of 6 – 8% and 4%, respectively; it is suggested that for optimum performance, this mixing ratio be used in the case of the red interlocking block. The increase in strength by Day 28 was 24% on average compared with the age of 3 days. By Day 91, strength improved by 18% on average compared with day 28. In case of the colored block, the strength of the (50mm) thick base layer was remarkably higher than that of (10mm) thick colored facing layer. However, in case of whole colored block, as the colored layer with low strength is located at the bottom of block, the flexural strength was considerably declined, compared with the partially colored block. The change in strength as a result of the concentration of pigment was as follows: The brown iron oxide and iron oxide pigment showed the highest strength at a mix ratio of 6 – 8% and 4%, respectively; it is suggested that this mix ratio be used to achieve optimum performance levels
SIFCON is a high-strength, high-performance material containing a relatively high volume percentage of steel fibers as compared to SFRC. It is also sometimes termed as ‘high-volume fibrous concrete’. The origin of SIFCON dates to 1979, Prof.Lankard carried out extensive experiments in his laboratory in Columbus, Ohio, USA and proved that, if the percentage of steel fibers in a cement matrix could be increased substantially, then a material of very high strength could be obtained, which he christened as SIFCON.
Concrete is mixture of cement, aggregate (fine and course), water and chemical admixture is also added when needed. About 75% of total concrete material is acquired by aggregate. So, it is important to choose the right type, quality and quantity of aggregate. The main matrix of concrete is made by aggregate. The aggregate particles are bounded with each other by cement and water. There are two types of aggregate: (1) coarse aggregate and (2) fine aggregate (sand). The course aggregate forms the main matrix and the fine aggregate forms the filter matrix by filling up the space between the course aggregate. With the
Concrete compressive strength is an important factor within the mechanical properties. In most building structures, concrete strength is used to resist compressive forces and support load act on the buildings. Compressive strength could be one of the basic measurement to review the overall quality of the concrete. Mindess et.al. (2003) states that water to cement ratio (w/c) has a great impact in the strength of the concrete. The higher the w/c, the lower the compressive strength. The lower the w/c, the higher the compressive
Conventional normal cement concrete is normally used as construction material of buildings. The impervious nature of concrete
Workability depends on water content, aggregate (shape and size distribution), cement content and age (level of hydration) and can be modified by adding chemical admixtures, like super plasticizer. Raising the water content or adding chemical admixtures will increase concrete workability. Excessive water will lead to increase bleeding (surface water) and segregation of aggregates (when the cement and aggregates start to separate), with the resulting concrete having reduced quality. Workability of fresh concrete is determined by following