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
The essential points of the green-frosting are the concentration and absorbance value in each diluted which the process of serial dilution. The standard curve of Blue#1 and yellow #5 provide the equation of the trend-line in order to calculate the concentration in the diluted solution of the green frosting. The mole of dye in 100mL green stock solution, mole of dye in 5 gram and 1 gram of frosting, the Beer –Lambert Law, and the compare to amount desired by the company can be determined. The Beer-Lambert Law is the relationship between color and the concentration and equation A=Ebc. The “A” is absorbance, the “C” is a concentration in molarity, the “E” is a molar absorptivity and “b” is the path-length. The goal of the lab is to use the absorbance and the Beer-Lambert law to determine the amounts of blue#1 and yellow #5 in the green frosting.
HYPOTHESIS: My hypothesis is that none of the Crayola colors are pure colors because they are a mixture of other color components.
When the hydrochloric acid was poured into marble chips, gas bubbles were seen – signifying the carbon dioxide (gas) that was being produced due to the chemical reaction.
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
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.
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 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
The job of SP is to impart a high degree of flow ability and deformability, however the high dosages generally associate with SCC can lead to a high degree of segregation. Conplast SP 430 is utilized in this project, which is a product of FOSROC Company having a specific gravity of 1.222. Super plasticizer is a chemical compound used to increase the workability without adding more water i.e. spreads the given water in the concrete throughout the concrete mix resulting to form a uniform mix. SP improves better surface expose of aggregates to the cement gel. Super plasticizer acts as a lubricant among the materials. Generally in order to increase the workability the water content is to be increased provided a corresponding quantity of cement is
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.
Strong color can usually be produced with less than 10% of added pigment. Different color intensities are achieved by varying the amount of coloring material or by mixing two or more pigments. Red, dark gray and other shapes are produced very satisfactorily by using normal cement. ACPA stated that admixtures that contain calcium chloride should be avoided since it can cause discoloration [39]. Buehrer et al, stated that adding extra water to increase the slump may cause excessive bleeding and non-uniformity in color, using any admixtures that contain calcium chloride should be avoided. Calcium chloride may cause salt deposits to be formed on the concrete surface and discolor it
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 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