巷道隔热喷射混凝土强度及导热性能试验研究

随着煤矿开采深度不断增加,巷道的高温热害问题尤为突出。在普通喷射混凝土中掺入陶粒、憎水玻化微珠、粉煤灰以及改变砂子的用量来设计正交试验,研究混凝土的抗压强度、抗拉强度、抗折强度和导热系数的变化。试验结果表明:憎水玻化微珠是影响混凝土的导热系数、抗压、抗拉和抗折强度的主要因素,因此憎水玻化微珠掺量宜选在100%;陶粒是影响混凝土抗折强度的主要因素,贡献率高达60.61%,因此陶粒的掺量在20%最优;随着粉煤灰掺量的增大,导热系数先降低后增大,强度先提高后降低,因此粉煤灰掺量宜为20%;随着砂子用量的降低,导热系数一直在降低,抗压强度和抗拉强度先提高后降低,抗折强度一直在提高,因此砂子用量在571 kg/m³最优。

Experimental Study on Thermal Conductivity and Strength of Thermal Shotcrete in Roadway

High temperature damage on roadway had been particularly outstanding with the increment of mining depth.By mixing ceramsite,hydrophobic vitrified beads,fly ash and changing the dosage of sand in ordinary shotcrete,we designed orthogonal experiment to researching the variations of compressive strength,tensile strength,flexural strength and heat conductivity coefficient.Experimental results show that hydrophobic vitrified bead is a dominant factor that affects the strengths and heat conductivity coefficient of concrete,hence we recommend the optimum dosage of hydrophobic vitrified beads as 100％.Ceramsite is also a major factor affecting the flexural strength,with a contribution rate up to 60.61％ and therefore we conclude the optimum ceramsite dosage to be 20％.With the increasing of fly ash content,heat conductivity coefficient firstly reduced and subsequently increased;while the strength of shotcrete is on the contrary.Finally,with the decline of sand dosage,heat conductivity coefficient had been reducing all the time whereas flexural strength had been increasing,and compressive and tensile strength firstly increased and then reduced;therefore the optimum sand dosage is 580 kg/m3.