How much fly ash should be added to concrete?
How much fly ash should be added to concrete?
Typically, fly ash is added to structural concrete at 15-35 percent by weight of the cement, but up to 70 percent is added for mass concrete used in dams, roller-compacted concrete pavements, and parking areas. Special care must be taken in selecting fly ash to ensure improved properties in concrete.
What is the correct proportional mixture for concrete?
The safest bet for any concrete mix is four-two-one: four parts crushed rock; two parts sand; and one part cement. The four-two-one mix, obviously, has seven parts. Conveniently, when mixing concrete, the ratio can be mixed on any range of scales.
How much fly ash can be used in concrete as per IS code?
The fly ash added in ppc should not be less than 15% and not more than 35%. According to IS code you can replace portland cement by max 35% of fly ash content. Many people tried replacing opc with 50% or more using fly ash – it termed as high volume fly ash concrete (HVFC).
What does too much fly ash do to concrete?
Slower Strength Gain The addition of fly ash can increase the length of time concrete takes to reach its full strength. This can cause problems when slow strength gain means delays in construction.
How much fly ash content is used in PPC?
PPC is manufactured either by inter-grinding Portland cement clinker, gypsum and fly ash obtained from thermal power plants or by intimately blending OPC and fly ash. The percentage of fly ash in PPC permitted by IS:1489 varies from 15% (in minimum) to 35% (maximum).
What is the strongest concrete mix ratio?
Strong Concrete Mix Ratio In making concrete strong, these ingredients should usually be mixed in a ratio of 1:2:3:0.5 to achieve maximum strength. That is 1 part cement, 2 parts sand, 3 parts gravel, and 0.5 part water.
How is WC ratio calculated?
The water to cement ratio is calculated by dividing the water in one cubic yard of the mix ( in pounds) by the cement in the mix (in pounds). So if one cubic yard of the mix has 235 pounds of water and 470 pounds of cement- the mix is a . 50 water to cement ratio.
What percentage of fly ash is mixed with Portland cement?
Approximately 15 to 30%
Approximately 15 to 30% of ordinary Portland cement is replaced with fly ash in Portland pozzolana cement. The compressive strength of Portland pozzolana cement is more for long term use compared to ordinary Portland cement. Ordinary Portland cement is one of the widely used cement.
How do you mix flyash with cement?
Typically, 15 percent to 30 percent of the portland cement is replaced with fly ash, with even higher percentages used for mass concrete placements. An equivalent or greater weight of fly ash is substituted for the cement removed. The substitution ratio for fly ash to portland cement is typically 1:1 to 1.5:1.
What percentage of fly ash is mixed with portland cement?
15 percent to 30 percent
Typically, 15 percent to 30 percent of the portland cement is replaced with fly ash, with even higher percentages used for mass concrete placements. An equivalent or greater weight of fly ash is substituted for the cement removed. The substitution ratio for fly ash to portland cement is typically 1:1 to 1.5:1.
Which is better OPC or PPC?
PPC cement is generally used for plastering, brick masonry and waterproofing works. PPC has a lower heat of hydration and it is prone to fewer cracks compared to OPC. PPC has lower strength than OPC but PPC provides better workability and finishing than OPC. PPC provides greater resistance to chemicals.
What is a 1 2 3 mix for concrete?
Concrete is made from cement, sand, gravel and water. In making concrete strong, these ingredients should usually be mixed in a ratio of 1:2:3:0.5 to achieve maximum strength. That is 1 part cement, 2 parts sand, 3 parts gravel, and 0.5 part water.
How do you make super strong concrete?
To make the concrete stronger, add more cement or less sand. The closer you bring the ratio to an even one-to-one of sand to cement, the stronger the rating becomes.
What is the maximum w/c ratio?
Studies show that capillary pores start to connect with each other when w/c is higher than 0.40. When w/c is higher than 0.70 all capillary pores are connected. So most of the standards recommend 0.70 as the maximum value for w/c ratio. Higher is the aggressiveness of the environment lower should be the w/c ratio.
What is the difference between Class C and Class F fly ash?
Class C provides concrete strength in the early stages of construction while Class F provides strength and lessens permeability in the long run. Due to its higher silica content, Class F fly ash is considered to be more effective compared to Class C fly ash.
What happens when fly ash is mixed with portland cement?
The use of fly ash in concrete as a partial replacement of cement can give technical advantages such as improved workability, strength, and durability of concrete [3-5]. In the 1950s, high strength concrete was defined as concrete with a compressive strength of 34 MPa (5000 psi) at 28-days.
Which is costly OPC or PPC?
Cost. The cost of OPC is around 300 rupees per bag which is slightly more expensive than PPC. Whereas in the case of PPC, the expensive clinker is replaced by pozzolanic Material such as fly ash hence the price of PPC is slightly less than who OPC.
Where is PPC cement used?
Portland Pozzolana Cement (PPC) It can be confidently employed in construction of hydraulic structures, marine works, mass concreting such as dams, dykes, retaining walls foundations and sewage pipes. It is also suitable for use in common applications such as masonry mortars and plastering.
What is the application of 1/3 3 ratio?
One of the best concrete mixing ratios for a slab is 1 : 3 : 3 (cement : sand : stone), this will produce approximately a 3000 psi concrete mix.
What is mix proportion?
In a given concrete mixture, the ratio of cement to sand to gravel, in terms of either dry, loose volume or dry weight.
How do you make ultra high performance concrete?
The mixing process is as follows: The silica sand and silica fume are first dry-mixed for about five minutes. Cement and GGBS are added to the mixture and dry-mixed for another five minutes. Water and HRWR are first mixed together and then added gradually to the dry material.