不同岩性整形机制砂混凝土的力学性能研究

Study on the Mechanical Properties of Concrete Made from Shaped Manufactured Sand of Different Lithologies

摘要:

整形机制砂具有优异的力学性能，因而在传统建材中能够替代河砂而得到广泛地应用。为了研究整形后不同岩性及大掺量整形机制砂混凝土的力学性能，利用塌落度筒和混凝土流变仪测试混凝土工作性能和流变性能，同时进行抗压强度的力学性能试验。结果表明；整形机制砂混凝土的塌落度随着机制砂掺量的增加而降低，同时其塑性粘度和抗压强度随着整形机制砂掺量的增加呈现先升高后降低的趋势；整形鹅卵石和整形花岗岩混凝土的屈服强度均随掺量的增加而降低，整形山砂混凝土的屈服强度与塑性粘度的变化相一致；整形鹅卵石、整形花岗岩及整形山砂在机制砂混凝土中的最优替代率分别为30%、40%和50%，而整形山砂在工作性能、流变性能和力学性能上方面均优于整形鹅卵石和整形花岗岩。

Abstract:

In traditional building materials， excellent mechanical properties are the key to the widespread use of high-mix shaped manufactured sand as an alternative to river sand. In order to clarify the mechanical properties of shaped concrete with large admixture of manufactured sand， this paper uses the slump cylinder and concrete rheometer to test the workability and rheological properties of concrete and conduct mechanical properties tests of compressive strength to investigate the workability， rheological properties and mechanical properties of the shaped manufactured sand in concrete with three different lithologies and admixtures， respectively. The results of the study shows that the slump of the concrete with shaped manufactured sand decreases with the increase of the sand admixture. At the same time， the plastic viscosity and compressive strength of the concrete with shaped manufactured sand showed a tendency of increasing and then decreasing with the increase of the amount of shaped manufactured sand. The yield strength of both shaped cobble and shaped granite concrete decreased with increasing admixture， and the yield strength of shaped mountain sand concrete was consistent with the change in plastic viscosity. Finally， the optimum replacement rates for shaped pebbles， shaped granite and shaped mountain sand in manufactured sand concrete were 30%， 40% and 50%， respectively. When compared， shaped mountain sand outperformed shaped cobblestone and shaped granite in terms of workability， rheological properties and mechanical properties.