## Hot Informations

• ##### 7 days concrete strength - Civil/Environmental engineering ,

10-04-2012· The concrete strngth of seven days must be 75percent of 30MPa minimemu required for 28days ie must be 225MPaIf it is different the mix design is improper or no enough cement in itPlease redesign again RE: 7 days concrete strength GavL (Civil/Environmental) 21 Jan 12 06:41...

• ##### 7 Days Compressive Strength of Concrete - Concrete ,

22-04-2005· RE: 7 Days Compressive Strength of Concrete whyun (Structural) 11 Apr 05 21:06 The rate of curing depends on many factors but assuming type I cement and moist cured at 70 degree fahrenheit, try the following equation: f'c (t) = f'c (28) * { t / (4 + 085t) } where f'c (t) represents the compressive strength at age t and f'c (28) represents ....

• ##### 7 days concrete strength - Civil/Environmental engineering ,

10-04-2012· The concrete strngth of seven days must be 75percent of 30MPa minimemu required for 28days ie must be 225MPaIf it is different the mix design is improper or no enough cement in itPlease redesign again RE: 7 days concrete strength GavL (Civil/Environmental) 21 Jan 12 06:41...

• ##### What should be the compressive strength of a C30 concrete ,

Answer (1 of 2): At 7 days, you should have 65% of the strength of the 28 days strength of any concrete made with OPC The 28 day strength of OLD C30 concrete ,...

• ##### Compressive strength of cement at 7 days & 28 days - Civil Sir

Compressive strength of cement at 7 days & 28 days Compressive strength of cement is determined by cube test on cement mortar cubes compacted by means of a standard vibration hydraulic machine Standard vibration for making cube is 12000 +- ,...

• ##### 7 day concrete strength - Structural engineering general ,

02-03-2003· If the concrete was supplied from a batch plant, the thing you should ask for is the "age-strength correlation" not the strength gain curves, as the former will give a better estimate of the predicted strength based on the true 28days strength using different Q/C systems such as the CUSUM which most of the concrete suppliers use to predict the 28-days strengths based on the 7-days ,...

• ##### Compressive Strength of Concrete -Cube Test, Procedure ,

Compressive strength achieved by concrete at 7 days is about 65% and at 14 days is about 90% of the target strength Which test is most suitable for concrete strength? A concrete cube test or concrete cylinder test is generally carried out to assess the strength of concrete after 7 days, 14 days or 28 days of casting...

• ##### 7-day vs 28-day compressive strength tests - Concrete ,

12-10-2008· As for validity, the 28-day test not only verifies the design compressive strength, it validates the 7-day test To delete the 28-day test prevents the use of a moving average as required for evaluation of strength on larger projects Suppose the 7-day specimen got mis-marked and was from a project that had 5000 psi concrete...

• ##### How much concrete strength do I need in 7 days? – AnswersToAll

24-04-2021· Compressive strength achieved by concrete at 7 days is about 65% and at 14 days is about 90% of the target strength What is the unit of compressive strength? The compressive strength is calculated from the failure load divided by the cross-sectional area resisting the load and reported in units of pound-force per square inch (psi) in US Customary units or megapascals (MPa) in ,...

• ##### What is the approximate ratio of 7 days compressive ,

Explanation: The 7 days compressive strength is approximately 065 times the 28 days compressive strength of cement concrete Strength of concrete is generally tested after 28 days as concrete cube strength because concrete gains strength with time after castingIt takes much time for concrete to gain 100 % strength and the time for the same is still unknown...

• ##### 7-day vs 28-day compressive strength tests - Concrete ,

12-10-2008· As for validity, the 28-day test not only verifies the design compressive strength, it validates the 7-day test To delete the 28-day test prevents the use of a moving average as required for evaluation of strength on larger projects Suppose the 7-day specimen got mis-marked and was from a project that had 5000 psi concrete...

• ##### Concrete Compressive Strength Variation with Time - The ,

The compressive strength gained by concrete is thus measured at its 28th day after which the rate of strength is lowered The compressive strength gained at later ages are tested by means of non-destructive tests The table-1 below shows the rate of strength gained from the first day to 28th day Table1: Strength Gained by Concrete With Age...

• ##### What is the approximate ratio of 7 days compressive ,

Explanation: The 7 days compressive strength is approximately 065 times the 28 days compressive strength of cement concrete Strength of concrete is generally tested after 28 days as concrete cube strength because concrete gains strength with time after castingIt takes much time for concrete to gain 100 % strength and the time for the same is still unknown...

• ##### Concrete 3-Day, 7-Day and 28-Day Strength Test Results and ,

🕑 Reading time: 1 minute The standard concrete compressive strength test is carried out at 28 days 3-days and 7-days concrete tests are carried out only to monitor the early strength gain and are useful in construction where high early strength of concrete is required as per construction documents But the values of 3-days and [,]...

• ##### compressive strength of concrete after 7 days

concrete compressive strength at 7 days - concrete compressive strength at 7 days - Crusher Give us your email address and we'll contact you shortly CQC: ISO9001:2000 Certificate: CE Brand Name: SBM Model ....

• ##### Predicting 28 Days Compressive Strength of Concrete from 7 ,

This paper presents a simple mathematical model to predict the compressive strength of concrete at 28 day from early age (say 7 days) results The model is a simple equation (a rational polynomial ....

• ##### Relationship Between Seven- and 28-Day Strengths| Concrete ,

01-10-1994· Concrete, by Mindness and Young, gives a general rule: The ratio of 28-day to seven-day strength lies between 13 and 17 and generally is less than 15, or the seven-day strength is normally between 60% to 75% of the 28-day strength and usually above 65% The cylinder that broke at 1980 psi is 66% of the specified 3000 psi...

• ##### How strong is concrete after 7 days? - Quora

Answer (1 of 9): The strength of concrete at 7 days is only 60–65% of design strength depending on external conditions Concrete gain its strength with time after casting The rate of gain of concrete compressive strength in higher during the first 28 days of casting and then it slows down The ....

• ##### Standards for 7-day and 28-day strength test results

A According to section 19213 of ACI 318-19 the specified compressive strength shall be based on the 28-day test results unless otherwise specified in the construction documents 3- or 7-day test results are used to monitor early strength gain, especially when high early-strength concrete is used However, 3- and 7-day test results are not ....

• ##### 7 day concrete strength - Structural engineering general ,

02-03-2003· If the concrete was supplied from a batch plant, the thing you should ask for is the "age-strength correlation" not the strength gain curves, as the former will give a better estimate of the predicted strength based on the true 28days strength using different Q/C systems such as the CUSUM which most of the concrete suppliers use to predict the 28-days strengths based on the 7-days ,...

• ##### 7 day concrete strength - Structural engineering general ,

02-03-2003· If the concrete was supplied from a batch plant, the thing you should ask for is the "age-strength correlation" not the strength gain curves, as the former will give a better estimate of the predicted strength based on the true 28days strength using different Q/C systems such as the CUSUM which most of the concrete suppliers use to predict the 28-days strengths based on the 7-days ,...

• ##### 3000 Psi concrete compressive strength at 3, 7, 21 and 28 ,

3000 Psi concrete compressive strength at 3, 7, 21 and 28 days As per ACI standard, compressive strength of concrete measured in Psi (Pounds per square inch) A higher psi means a given concrete mixture is stronger, so it is usually more expensive and lower Psi means a given concrete mixture is on average strength...

• ##### (PDF) Relationship between 7 and 28 days CS (compressive ,

Relationship between 7 and 28 days CS (compressive strength) for HSC (high-strength concrete) by use of ANN (artificial neural network) and regression methods January 2010 Asian Journal of Civil ....

• ##### Why We Test Concrete Compressive Strength after 28 Days?

14-08-2014· When, its strength have reached 99% in 28 days, still concrete continues to gain strength after that period, but that rate of gain in compressive strength is very less compared to that in 28 days After 14 days of casting concrete, concrete gains only 9% in next 14 days So, rate of gain of strength ,...

• ##### Concrete compressive strength at an age of t days

Eurocode 2 part 1-1: Design of concrete structures 312 (5) The concrete compressive strength at an age of t days is: fck ( t) = fcm ( t) - 8 (MPa) for 3 < t < 28 days fck ( t) = fck for t ≥ 28 days where: fck is the characteristic compressive cylinder strength of concrete at 28 days according to Table 31...

• ##### 7 day concrete strength - Structural engineering general ,

02-03-2003· If the concrete was supplied from a batch plant, the thing you should ask for is the "age-strength correlation" not the strength gain curves, as the former will give a better estimate of the predicted strength based on the true 28days strength using different Q/C systems such as the CUSUM which most of the concrete suppliers use to predict the 28-days strengths based on the 7-days ,...

• ##### Concrete Compressive Strength Variation with Time - The ,

The compressive strength gained by concrete is thus measured at its 28th day after which the rate of strength is lowered The compressive strength gained at later ages are tested by means of non-destructive tests The table-1 below shows the rate of strength gained from the first day to 28th day Table1: Strength Gained by Concrete With Age...

• ##### Day Compressive Strength - an overview | ScienceDirect Topics

07-01-1999· At an equivalent 28-day compressive strength, concrete containing fly ash typically achieves a lower 7-day strength compared to concrete without fly ash However, an equivalent early-age strength can be achieved with the use of accelerators, water-reducing admixtures, and/or by modifying the mix proportions...