Self-compacting concrete (SCC) is known as a high-performance concrete that molds by its weight and without the need for vibration or impact and easily crosses the small spaces between the rebars. Various additives have been used in recent research to construct the self-compacting concrete in order to achieve higher strengths and improved performances. Because of the utilization of self-compacting concrete in bulk concreting like dams, silos, and tanks, the optimized use for reducing the final costs of the project is important and essential. A fundamental question in improving the fiber self-compacting concrete behavior is that what is the optimum amount of fiber addition for low fiber concentrations. In this research, the effect of the addition of fiber with concentrations lower than 1,000 gr (100, 250, 500, and 1,000 gr) on the self-compacting concrete behavior with different fiber lengths have been studied. This research examined the effect of the quantity and length of recycled plastic fiber on the compressive strength and tensile resistance of self-compacting concrete. Slump flow experiment L box and sieve and compressive and tensile strength experiment were done on samples. In this study, 13 plans of concrete mixing were surveyed with ratio of water to cement 0.4. One plan without fiber was chosen as a reference sample and 12 self-compacting concrete with plastic Fibers were made in the laboratory with dimensions of 1, 2, 3 cm with their amounts equal 100, 250, 500 and 1,000 g/m³. Laboratory results showed that increasing the amount and length of fibers led to decreased flowability and passability plus increased detachment in samples. By increasing plastic fibers, compressive strength increased by 8.4% and tensile resistance increased by 4.22%. Their elevation depends on fibers amount. Fiber length did not affect the compressive strength and tensile resistance very much. The increase was such that the tensile strength increased by about 100% and 200% as the length increased from 1 to 2 cm and 1 to 3 cm, respectively. The 1 cm plastic fiber length could be selected as the optimum length for increasing the compressive strength by considering the efficiency.

自密实混凝土（SCC）是一种高性能混凝土，它因自身重量而模制，而无需振动或冲击，并且很容易穿过钢筋之间的狭小空间。为了获得更高的强度和改善的性能，最近的研究中已经使用各种添加剂来构造自密实混凝土。由于在大坝，筒仓和储罐等大体积混凝土中利用了自密实混凝土，因此优化使用量以降低项目的最终成本至关重要，这一点至关重要。改善纤维自密实混凝土性能的一个基本问题是，对于低纤维浓度，最佳的纤维添加量是多少。在这项研究中，添加浓度低于1,000 gr（100、250、500和1，000 gr）对不同纤维长度的自密实混凝土的性能进行了研究。本研究研究了再生塑料纤维的数量和长度对自密实混凝土抗压强度和抗拉强度的影响。对样品进行了坍落流动试验L箱和筛网以及抗压和抗张强度试验。在这项研究中，调查了13个混凝土搅拌计划，水灰比为0.4。选择了一个不含纤维的方案作为参考样品，并在实验室中制备了12种带有塑料的自密实混凝土，纤维的尺寸为1、2、3厘米，其量分别为100、250、500和1,000 g / m 这项研究研究了再生塑料纤维的数量和长度对自密实混凝土抗压强度和抗拉强度的影响。对样品进行了坍落流动试验L箱和筛网以及抗压和抗张强度试验。在这项研究中，调查了13个混凝土搅拌计划，水灰比为0.4。选择了一个不含纤维的方案作为参考样品，并在实验室中制备了12种带有塑料的自密实混凝土，纤维的尺寸为1、2、3厘米，其量分别为100、250、500和1,000 g / m 本研究研究了再生塑料纤维的数量和长度对自密实混凝土抗压强度和抗拉强度的影响。对样品进行了坍落流动试验L箱和筛网以及抗压和抗张强度试验。在这项研究中，调查了13个混凝土搅拌计划，水灰比为0.4。选择了一个不含纤维的方案作为参考样品，并在实验室中制备了12种带有塑料的自密实混凝土，纤维的尺寸为1、2、3厘米，其量分别为100、250、500和1,000 g / m³。实验室结果表明，增加纤维的数量和长度会导致流动性和通过性降低，并增加样品的分离性。通过增加塑料纤维，抗压强度提高了8.4％，抗拉强度提高了4.22％。它们的高度取决于纤维量。纤维长度并没有很大地影响抗压强度和抗拉强度。这种增加使得当长度从1到2 cm和1到3 cm分别增加时，拉伸强度分别增加了约100％和200％。通过考虑效率，可以选择1 cm的塑料纤维长度作为增加抗压强度的最佳长度。