According to section 19.2.1.3 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.

The compressive strength test is performed on 15 cm × 15 cm × 15 cm cube, Metalic mould is used for casting concrete cubes. Fresh concrete is filled in three layers in a mould and each layer is compacted 25 times by tamping road, sometimes vibration table is used for compaction of the cube.

Compressive strength as a concrete property depends on several factors related to quality of used materials, mix design and quality control during concrete production. Depending on the applied code, the test sample may be cylinder [15 cm x 30 cm is common] or cube [15 cm x 15cm x 15 cm is the most common].

As per BS 8500-2 British/European standards The grade of concrete is denoted as C10, C15, C20, C25, etc., ‘C’ which means ‘Concrete Strength class’ and number behind C refers to characteristic Compressive strength of Concrete in N/mm2 @ 28 days when tested with the 15 cm dia. & 30 cm height cylinder in a direct compression test.

In simpler words, HPC is a concrete that has atleast one outstanding property viz. Compressive Strength, High Workability, Enhanced Resistances to Chemical or Mechanical Stresses, Lower Permeability, Durability etc. as compared to normal concrete.

Tests and Acceptance Criteria for Concrete Based on Compressive Strength Diwan Singh Bora, IDSE M-Tech Structure IIT Madras Abstract: This article summarizes current practices for testing of concrete and comparing with the acceptability criteria as per IS based on compressive strength.

For calculating Compressive strength (C.S) of the concrete, it’s given as: Compressive Strength = Ultimate load (N)/ Cross sectional area (m㎡). Cross sectional area = 150 mm x 150mm = 22500 m㎡ If any of the specimen Compressive Strength result Varies by more than 15% of the average results, the result is rejected. Result obtained: Average

The mean compressive strength required at a specific age, usually 28 days, determines the nominal water-cement ratio of the mix. The other factor affecting the strength of concrete at a given age and cured at a prescribed temperature is the degree of compaction.

Compressive Strength—The advanced compressive strength of UHPC is particularly significant when comparing to traditional concrete. While traditional concrete normally has a compressive strength ranging anywhere from 2,500 to 5,000 psi, UHPC can have a compressive strength of up to 10 times that of traditional concrete.

Compressive strength of concrete is the resistance provided by concrete when a compressive load is applied to it. Concrete has very high compressive strength. Most of the design of concrete structures is done by adopting the value of its compressive strength. Generally, concrete is used for the member of compressive strength because:

Compressive Strength of Concrete. The compressive strength test results for M30 and M60 grades of concrete are shown in Table 3 for both 14 and 28 days of curing. In the case of M30 grade, it is seen that the compressive strength initially increases, reaches a peak at 1% fibre content and later reduces for both 14 and 28 days of curing.