ABSTRACT

The purpose of the study was to use waste rice husk ash (RHA), residual ash generated at the rice husk fuelled clay brick kiln, for manufacturing paving blocks. Strength, durability, water quality of the paved surface run-off and microstructure of specimens were examined. Cement in paving blocks was partially replaced by five percentage of waste RHA: 0%, 5%, 10%, 15%, and 20% (by weight). At 10% waste RHA, paving block structure became denser than the conventional block, and 56-day compressive strength was improved by 18.1% and 26.5% for M15 (Grade 15) and M25 (Grade 25) blocks, respectively. Paving blocks with 10% waste RHA achieved splitting tensile strength and flexural strength greater than that of the conventional blocks. At all waste RHA levels, sulfate resistance was improved, water absorption was ranged 3–6% and British Pendulum Number was found to be higher than 45, satisfying the limits specified in standards. For the run-off, total suspended solids concentration was less than 6 mg/l, turbidity was ranged 2.15–3.57 NTU, conductivity was ranged 74.0–137.0 μs/cm and satisfied the limits in standards. This study concludes 10% of waste RHA without any pre-processing can be used as a cement replacement in paving blocks.

摘要

该研究的目的是使用废稻壳灰 (RHA)，即稻壳为燃料的粘土砖窑产生的残余灰烬，用于制造铺路砖。对铺装路面径流的强度、耐久性、水质和试样的微观结构进行了检查。铺路砖中的水泥被 5% 的废 RHA 部分替代：0%、5%、10%、15% 和 20%（按重量计）。在 10% 的废 RHA 下，铺路砖结构比常规砖更致密，M15（15 级）和 M25（25 级）砖的 56 天抗压强度分别提高了 18.1% 和 26.5%。含 10% 废 RHA 的铺路砖的劈裂抗拉强度和抗弯强度均高于传统砖。在所有废物 RHA 水平下，硫酸盐抗性都得到了改善，吸水率范围为 3-6%，英国摆数高于 45，满足标准规定的限制。对于径流，总悬浮固体浓度小于 6 mg/l，浊度范围为 2.15-3.57 NTU，电导率范围为 74.0-137.0 μs/cm，满足标准限制。这项研究得出结论，10% 的未经任何预处理的废 RHA 可用作铺路砖中的水泥替代品。