The Study on the Physical and Strength Properties of Lightweight Concrete by Replacement Ratio of Artificial Lightweight Aggregate

인공경량골재 혼합비율에 따른 경량 콘크리트의 물성 및 강도특성에 관한 연구

Abstract

This study is to compare and analyze the physical and strength properties of lightweight concrete using domestic lightweight aggregate by replacement ratio of artificial lightweight fine and coarse aggregate after considering low cement mixture and pre-wetting time. The slump, unit weight, compressive strength and split tensile strength of lightweight concrete with domestic lightweight aggregate were measured. As test results, the slump of lightweight concrete by replacement ratio of lightweight fine aggregate increased as the replacement ratio of lightweight fine aggregate increased. The unit weight of lightweight concrete using 100% of lightweight fine aggregate was about 10.4% lower than that of the lightweight concrete with natural sand. In addition, the unit weight of lightweight concrete by replacement ratio of lightweight coarse aggregate increased with the increase of the ratio of LWG10(5~10mm). The compressive strength of lightweight concrete with lightweight fine and coarse aggregate increased as the replacement ratio of lightweight fine aggregate increased. The compressive strength of lightweight concrete with natural sand and LWG10 was 30 to 31MPa regardless of the replacement ratio of the lightweight coarse aggregate after 7 days.

본 연구는 최근 사용량이 증대하고 있는 저시멘트 배합을 대상으로 국내생산 인공경량 잔 굵은골재의 혼합비율에 따른 경량콘크리트의 물성 및 강도특성을 비교 검토한 것으로서 실험결과, 프리웨팅 시간이 24시간 증가할 경우 모르타르 플로우값이 약 3~5% 감소하는 것으로 나타났으며 경량잔골재 사용에 의해 모르타르 배합에서 약 10.4%의 기건단위질량 감소효과를 얻을 수 있는 것으로 나타났다. 또한 경량굵은골재의 혼합비율에 따른 경량콘크리트의 기건단위질량은 5~10mm 크기인 LWG10 경량굵은골재의 혼합비율이 높아질수록 선형적으로 기건단위질량이 증가하였으며 LWG10 경량굵은골재를 혼합할 경우 LWG10 혼합비율에 관계없이 재령 7일에 약 30~31MPa 수준의 유사한 압축강도를 발현하였다.

Figure 1. Lightweight aggregate

Figure 2. Particle size distribution of NS and LS

Figure 3. Fineness modulus of fine aggregate by LS replacement ratio

Figure 4. Particle size distribution of lightweight coarse aggregate (SeriesⅢ)

Figure 5. Fineness modulus of lightweight coarse aggregate (SeriesⅢ)

Figure 6. Mortar flow (Series Ⅰ)

Figure 7. Compressive strength of mortar (Series Ⅰ)

Figure 8. Concrete slump (Series Ⅱ)

Figure 9. Slump test of lightweight concrete (Series Ⅱ)

Figure 10. Unit weight (Series Ⅱ)

Figure 11. Compressive strength (Series Ⅱ)

Figure 12. Split tensile strength (Series Ⅱ)

Figure 13. Concrete slump (SeriesⅢ)

Figure 14. Unit weight (SeriesⅢ)

Figure 15. Compressive strength (SeriesⅢ)

Figure 16. f_sp/ $\sqrt[]{f_c_k}$ (SeriesⅢ)

Table 2. Physical properties of aggregate

Table 3. Sieve analysis of aggregate

Table 1. Chemical composition of cementitious materials

Table 4. Mix proportions and test plan

Table 5. Measurement items