An Experimental Study of Beams Made of Autoclaved Aerated Concrete Masonry Units

The article represents experimental results obtained from four-point bending tests of beams, made of autoclaved aerated concrete (AAC) masonry units of D500 class, sawn and glued back together by special adhesive for AAC masonry. The aim was to develop the made-in-situ lintels which have not been sufficiently studied in the case of AAC block usage. The specimens in the current study include four beams, masonry units and specimens of the masonry. Two types of beams with a 1300 mm clear span were tested. In each beam, there was a reinforcement represented by two galvanized fully threaded M6 rods of 5.8 class. In the first two beams, steel bars were mounted externally as tie rods to provide the counteraction for a thrust on the supports. In the second pair of beams, steel bars were mounted inside the beams in predrilled holes. Steel bars in all beams were prestressed during making, which was achieved by a torque wrench. The obtained test data provide a basis for evaluating the accuracy of existing strength-design equations to predict the capacity of such beams. Test results show that the internal application of reinforcement at the bottom zone of the beams in combination with prestressing increases the load and deflection capacities. Both series of beams demonstrated, among other things, that the failure was accompanied by cracks in the tension zone and crushing of aerated concrete in the compressed zone in the pure bending zone as well as in the support zone due to shear.