不同龄期下蒸压粉煤灰砖砌体抗剪性能试验

摘要

目的 研究蒸压粉煤灰砖砌体抗剪强度随龄期变化规律与抗剪性能,为编制《蒸压粉煤灰砖建筑技术规范》提供试验依据.方法 按照砌体基本力学性能标准试验方法,先根据不同龄期将砂浆抗压试验分4组每组6个试件进行砂浆抗压强度试验,再通过24个砌体试件分别进行龄期为7d、14d、21d、28d蒸压粉煤灰砖砌体通缝抗剪试验,根据试验结果确定出砌体抗剪强度值并绘制出砂浆抗压强度随龄期变化关系曲线与蒸压粉煤灰砖砌体抗剪强度随龄期变化关系曲线.结果 蒸压粉煤灰砖抗剪强度为0.303MPa,高于蒸压粉煤灰砖规范设计值0.12MPa,蒸压粉煤灰砖砌体早期抗剪强度提高较快,其7d抗剪强度为28d抗剪强度的67.9％.结论 蒸压粉煤灰砖砌体破坏表现为单剪裂缝,破坏为脆性且主要发生在砂浆层与块体的粘结面,破坏面较平整,砌体抗剪强度的标准值及设计值可按规范取值,其结果偏于安全.%The purpose of this paper is to study the shear performance and variation law of autoclaved fly ash brick masonry under the different ages and also provide the experimental basis for the preparation of" Autoclaved Fly Ash Brick Building Technology Standard". The Method of the research is on the basis of the basic mechanics of masonry standard test approach. The different age compressive tests are divided into 4 groups with 6 specimens for each one for the compressive strength tests. The autoclaved fly ash brick masonry walls shear tests are respectively experimented under the ages of 7 d,14 d,21 d,28 d by means of 24 specimens. According to the test result,the masonry shear strength value is confirmed and the curves of mortar compressive strength and autoclaved fly ash brick masonry shear strength with age changing are drawn. The result of this research is that the autoclaved fly ash brick shear strength is up to 0. 303 Mpa, with the value higher than the autoclaved fly ash brick specification design for 0. 12 Mpa. Autoclaved fly ash brick masonry early shear strength rises much faster,The 7 d shear strength is 67. 9% times as much as the 28 d one. The Conclusion of this paper is that the autoclaved fly ash brick masonry performance for the single shear crack damage is brittle and the damage mainly lies in the mortar layer and destroys the adhesive surface,the ruining surface is smooth, the standard value of the masonry shear strength and the design value can be attained according to the code value, and the result is much safe.