Abstract
This study was carried out to determine the effect of accelerated curing on the strength of standard sand mortar and briquette ash mortar. The standard sand mortars and the briquette ash mortars made by mixture of the standard sand:cement and the briquette ash:cement at the ratio of 2 : 1, 3: 1 and 4 : 1, respectively, were cured at 4 different temperature of $20^{\circ}C$, $60^{\circ}C$, $80^{\circ}C$ and $100^{\circ}C$. The compression and tensil strength of mortars were measured at ${\sigma}_3$, ${\sigma}_7$, ${\sigma}_28$. The results obtained are summarized as follows; 1. At each age of curing and each curing temperature, the compression and tensile strength of the mortars made by the mixture of cement and standard sand was significantly higher than that of the mortars made by the mixture of cement and briquette ash. But the increasing rate of strength in compression and tension was significantly higher at the mortars of cement and briquette ash than those of cement and standard sand. 2. The strength of mortars which showed lower strength than Korean Standard at ordinary curing temperature was significantly increased and showed higher value than Korean Standard by the accelerated curing at high temperature. The increasing rate of strength by the accelerated curing was higher at the mortars containing less amount of cement than those containing more cement. The hardening of the mortars containing less amount of cement was significantly promoted by the accelerated curing in high temperature. 3. When the briquette ash was substituted for the materials of cement mortar, decline of the mortar strength is. unavoidable. But the enhancement of the mortar strength is still expected by the experimental results that the strength of cement-briquette ash mortar showed an increase of 137.6% by the accelerated curing at $60^{\circ}C$, 164.1% at $80^{\circ}C$ C and 183.8% at $100^{\circ}C$, respectively, compared with the strength of mortar cured at $20^{\circ}C$ for 28 days. 4. As the strength of cement briquette mortar is lower than that of cement standard sand mortar, the cement briquette ash mortar is expected to be increased in strength by the accelerated curing at high temperature. The cement briquette mortar is expected to be utilized to the production of secondary mortar goods or the constructions which need low strength of mortar.
본(本) 연구(硏究)는 촉진양생(促進養生)이 Mortar 압축강도와 인장강도에 미치는 영향과 시멘트 : 연탄재 Mortar에 미치는 영향을 연구(硏究)하기 위하여 시멘트 : 표준사, 시멘트 : 연탄재를 배합비(配合比) 1 : 2, 1 : 3, 1 : 4의 3종류(種類)로 하고 $20^{\circ}C$의 기준양생분(基準養生分)과 촉진온도(促進溫度)를 $60^{\circ}C$, $80^{\circ}C$, $100^{\circ}C$의 3 종류(種類)로 구분(區分)하고, ${\sigma}_3$, ${\sigma}_7$, ${\sigma}_28$의 압축(壓縮) 및 인장강도(引張强度)시험을 실시(實施)하였으며 본시험(本試驗)의 결과(結果)를 요약(要約)하면 다음과 같다. 1.압축(壓縮)과 인장강도(引張强度)에서 시멘트 : 표준사(標準砂)가 시멘트 : 연탄재보다 각재령(各材令), 각온도(各溫度)에서 강도(强度)는 현저히 크게 나타났으나 강도(强度)의 증가율(增加率)은 시멘트 : 연탄재가 시멘트 : 표준사보다 각재령(各材令)과 각온도(各溫度)에서 크게 나타났다. 2. 압축(壓縮)과 인장강도(引張强度)에서 KS 규정치(規定値) 하(下) 회(廻)하던 것이 촉진양생(促進養生)의 온도상승(溫度上昇)으로 규정치(規定値)를 상회(上廻)하게 된 것은 촉진양생(促進養生)에 의한 강도(强度)의 증가(增加)라고 생각되며 촉진양생(促進養生)에 의한 강도(强度)의 증가율(增加率)이 부배합(富配合)보다 빈배합(貧配合)에서 크게 나타난 것은 빈배합(貧配合)일수록 촉진양생(促進養生)에 의한 경화작용(硬化作用)이 더 활발(活潑)히 진행(進行)된다는 것을 예측(豫測)할수 있다. 3. 시멘트 모르터에서 잔골재를 연탄재로 대치(代置)했을 때 강도저하는 불득기(不得己)한 것이지만 시멘트 : 연탄재의 ${\sigma}_28$의 강도(强度)를 $20^{\circ}C$에서 100%로 보았을 때 촉진양생온도(促進養生溫度) $600^{\circ}C$에서 137.6%, $80^{\circ}C$에서 164.1^, $100^{\circ}C$에서 183.8%의 평균증가(平均增加)를 보이고 있어 강도(强度)의 증가(增加)를 기대(期待)할수 있다. 4. 시멘트 : 연탄재의 모르터는 시멘트 모르터에 비(比)하여 저강도이지만 촉진양생(促進養生)의 온도조절(溫度調節)로 강도증진을 기대(期待)할수 있기 때문에 저강도를 요(要)하는 곳과 시멘트 2 차제품(次製品)의 제조(製造) 등에 이용(利用)이 가능(可能)하다고 생각된다.
(Dept. of Agricultural Engineering, Coll. of Agriculture, Chungnam Natl. Univ.)