Experimental Study on Flexural Behavior of Simply Supported Beams with All-Light Shale Ceramsite Concrete

All-light shale ceramsite concrete (ALSCC) is a lightweight building material suitable for self-weight-sensitive flexural members in prefabricated and long-span structures, but experimental data on its flexural behavior remain limited. This study aims to characterize the physical and mechanical properties of ALSCC and evaluate its flexural behavior under the present test conditions through comparison with C30 normal concrete. Cubic material-property tests and four-point bending tests on simply supported beams were conducted. Material tests showed that the average density of ALSCC was 65.2% of that of normal concrete, while its cube compressive strength and splitting tensile strength were 80.6% and 82.3% of the corresponding values for normal concrete, respectively. Cracks in the ALSCC material specimens tended to propagate through the ceramsite aggregates, indicating a relatively brittle fracture response at the material level. Three ALSCC beams (AL-B1, AL-B2, and AL-B3) and one normal-concrete control beam (NC-B1) were tested to analyze failure modes, load–deflection responses, sectional strain distributions, and reinforcement-strain responses. Test results showed that the ALSCC beams exhibited typical under-reinforced flexural failure, with cracking loads of 5.0–6.5 kN and peak loads of 40.4–42.5 kN, which were comparable to the 41.6 kN peak load of the normal-concrete control beam. The peak loads of the ALSCC beams occurred at midspan deflections of 13.10–14.47 mm. Under continued displacement-controlled loading, maximum recorded midspan deflections of 38.01–40.45 mm were reached at test termination. Within the present test program, the ALSCC beams exhibited lower elastic-stage stiffness than the normal-concrete control beam, while approximately linear sectional strain distributions were observed within the measured load range. The reinforcement-strain responses of the ALSCC beams were also broadly comparable to the response of the control beam. This work provides preliminary material-specific experimental evidence on the flexural behavior of ALSCC simply supported beams under the present test conditions and provides a basis for further validation using larger specimen sets.