cf<\/sub> = F·L \/ (b·d²)<\/em>, where F is the maximum load, L the span, and b, d the section dimensions. Report to the nearest 0.1 MPa with specimen size, curing regime and fracture location.<\/p>\nAcceptance Criteria<\/h2>\n
Typical structural concrete achieves 3–5 MPa flexural strength at 28 days; rigid pavement specifications commonly require a characteristic value of 4.0–4.5 MPa. If fracture falls outside the middle third by more than 5% of the span (third-point method), the result is discarded.<\/p>\n
Frequently Asked Questions<\/h2>\nCentre-point or third-point loading \u2014 which should I use?<\/h3>\n
Third-point loading (ASTM C78, EN 12390-5) stresses the whole middle third equally and gives more representative, slightly lower values than centre-point loading (ASTM C293), which forces failure at one section. Specify the method when reporting.<\/p>\n
Can flexural strength be estimated from compressive strength?<\/h3>\n
Only approximately \u2014 correlations such as 0.7√f’c are mix-specific. Pavement acceptance should always use measured beam results, not converted cube or cylinder values.<\/p>\n
Recommended Apparatus<\/h2>\n
NL Scientific manufactures the Fully Automatic Flexural Testing Machine for FIBER-REINFORCED Concrete 300kN<\/a> for this method. Browse the full Concrete Testing Equipment<\/a> range or request a quotation<\/a> from our engineers.<\/p>\n
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