STUDY ON WORKABILITY AND STRENGTH OF LOW-STRENGTH MORTAR WITH RECYCLED FINE AGGREGATE FOR BACKFILLING

Autor: Juetsu Sato, Makoto Kagaya
Rok vydání: 2013
Předmět:
Zdroj: Cement Science and Concrete Technology. 67:565-572
ISSN: 2187-3313
0916-3182
DOI: 10.14250/cement.67.565
Popis: The purpose of this experimental study is to obtain the reference value of workability characteristics, strength test age and curing method of low-strength mortar with self-compactability for backfill. Two types of ordinary cement (produced with and without burnt rubble caused by Tsunami), two types of low quality recycled fine aggregate without treatment as fine aggregate, high volume fly ash and superplasticizers were used. The recycled fine aggregate was manufactured by only original crushing after demolishing old concrete bridge piers and buildings. The workability was measured by flow value and bleeding ratio. The target values were decided to be 250 to 300 and less than 3.0％ from many test results and references respectively. The target range of the compressive strength was 0.3 to 2.0N/mm₂. It was clarified that the suitable age of strength test was 91 days cured in moist sand with excessive water in the laboratory because of showing almost constant strength after this age. The mortar prismatic test pieces were laid underground for three months and one year at two locations where weather condition was very different. The strength of test pieces laid underground at both locations showed that of target range. These results were previously confirmed by the laboratory cured test. The validity of laboratory cured strength test was verified from these results. These information will be able to make use of evaluating workability and strength of low- strength mortar with recycled fine aggregate for backfilling.本研究は、自己充填性を有する埋戻し材用低強度モルタルのワーカビリティー特性、強度試験材齢および養生方法の基準値と試験方法を明らかにすることを目的とした。2種類の普通セメント（普通、瓦礫由来）、2種類の低品質再生細骨材、多量のフライアッシュおよび高性能AE減水剤を使用した。フロー値およびブリーディング率の目標値は、250～300および3.0％未満、圧縮強度の目標範囲を0.3～2.0N/mm₂とした。湿砂に余剰水を加えた中で供試体を91日間養生して、強度試験を実施した。フロー値、ブリーディング率および強度が室内試験で目標値に達していれば、地中に埋設された場合でも所要の強度が得られることを気象条件の異なる2地点で検証した。
Databáze: OpenAIRE
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