【作者】 程多松；

【导师】 尚建丽；

【作者基本信息】 西安建筑科技大学 ， 材料学， 2007， 硕士

【摘要】 轻集料混凝土因具有表观密度小、强度高、保温、隔热、耐火、抗震性能好等优良性能而得到迅速发展，现在已成为仅次于普通混凝土用量最大的一种混凝土。随着外加剂和矿物掺合料在轻集料混凝土中的应用，轻集料混凝土在高层建筑、大跨度桥梁等结构工程中将会有更加广阔的应用前景。由于轻集料自身的特点，近年来许多学者对轻集料混凝土的力学性能，诸如抗压强度、断裂性能、弹性模量等开展了研究。但是随着双掺技术的广泛应用，轻集料混凝土力学性能变化将会给轻集料混凝土质量控制带来很大的影响。因此本文针对双掺轻集料混凝土的抗压强度、断裂性能和弹性模量进行了试验研究。首先，通过对不同龄期(3d、7d、14d、21d、28d)轻集料混凝土抗压强度进行研究，研究单掺、双掺轻集料混凝土的抗压强度随龄期发展的规律，依据其规律运用数学方法进行早期预测轻集料混凝土强度。结果表明，采用本文建立的方程，预测精度较高，适用性较好；改变双掺轻集料混凝土中矿物掺合料的种类和掺量，研究矿物掺合料的掺量对轻集料混凝土的7d和28d抗压强度的影响。试验表明，7d时双掺轻集料混凝土强度均高于基准轻集料混凝土，但28d强度只有在最佳掺量时超过基准轻集料混凝土。通过宏观和微观分析了引起这种差别的原因。其次，通过测定不同龄期基准轻集料混凝土的抗压强度和劈拉强度，研究轻集料混凝土断裂性能随龄期的变化规律，即随着龄期的增长，轻集料混凝土的脆性增大；改变双掺轻集料混凝土中矿物掺合料的种类和掺量，研究轻集料混凝土的断裂性能和各矿物掺合料掺量的关系。对粉煤灰轻集料混凝土，当粉煤灰掺量为20％，轻集料混凝土的断裂脆性最大；对矿渣粉轻集料混凝土，当矿渣粉掺量为15％，轻集料混凝土的断裂脆性最大；对复合轻集料混凝土，复合掺量30％的条件下，粉煤灰：矿渣粉=2：4时，轻集料混凝土断裂脆性最大。最后，改变双掺轻集料混凝土中矿物掺合料的种类和掺量，研究轻集料混凝土的弹性模量和各矿物掺合料掺量的关系。对粉煤灰轻集料混凝土，当粉煤灰掺量为20％，轻集料混凝土的弹性模量最大；对矿渣粉轻集料混凝土，当矿渣粉掺量为15％，轻集料混凝土的弹性模量最大；对复合轻集料混凝土，复合掺量30％的条件下，粉煤灰：矿渣粉=2：4时，轻集料混凝土弹性模量最大。更多还原

【Abstract】 With many excellent characterictics of low apparent density, high strengh, heat preservation and insulation, high earthquake risistance, lightweight aggregate concrete (LAC) develops so rapidly that the quantity of LAC in use is greatest except ordinary concrete. As mineral additive and admixture are used in LAC, it has more large application in stuctural buildings, such as high-storeyed buildings and large-spanned bridges.Because of the particular characteristics of light aggregate, many scholars have researched mechanics characteristics of LAC, such as compressive strength, rupture characteristics and elastic modulus. As the double-additives techinology is in use, the changes of LAC’s mechanics characteristics have great influence on the control of LAC quality. Then the paper has given research on compressive strengh, rupture characterictics and elastic modulus of LAC by experiments.At first, the research of the strength at varied age in single-addition or double-additives situation gives the rules of the compressive strength of LAC as the age goes on. On the basis of the rules, the strength of LAC is estimated by the early-aged LAC compressive strength. And the result of the estimation is exact by the formula which is constructed by experiments. What’s more, the applicabilities of the rules are better.The research on the influences, which are given on 7 days’ and 28 days’ strength by the type and quantity of mineral additive, is done. And the experiments show that the strength of double-additives LAC is larger than that of normal LAC at the age of 7 days. However, only the best quantity of mineral additive can make the strength of double-additives LAC larger than that of normal LAC at the age of 28 days. Then the results of this situation are analyzed in macroscopical and microcosmic ways.In the next place, the rule of rupture of LAC, which displays that the brittleness of LAC goes higher as time goes on, is researched by compressive strength and tensile strength at varied age. The relation between rupture of LAC and quantity of additive and kind of additive is researched by adding varied kind additive by different quantity. The results are as follows: the rupture of fly ash LAC is highest at the percent of 20 for fly ash quantity added; the rupture of slag LAC is highest at the percent of 15 for slag quantity added; the rupture of compound admixture LAC is highest when the proportion of fly ash and slag is in the proportion of 2:4 and the total percent of additive is 30.At last, the relation between elastic modulus of LAC and quantity of minerral additive and kind of admixture is researched by adding varied kind additive and adding different quantity. The results are as follows: the modulus of fly ash LAC is highest at the percent of 20 for fly ash quantity added; the modulus of slag LAC is highest at the percent of 15 for slag quantity added; the modulus of compound admixture LAC is highest when the proportion of fly ash and slag is in the proportion of 2:4 and the total percent of admixture is 30.更多还原