METHOD FOR CONTROLLING TEMPERATURE FOR KNEADING CONCRETE

摘要

PURPOSE: To adequately control the temp. for kneading concrete by supplying liquified gas by a special technique into the concrete. CONSTITUTION: The necessary amt. W0 (kg) of the liquefied gas to be supplied is set by equation 1 at the time of starting placement. In the equation 1, W0 is the amt. (kg) of the liquefied gas to be supplied; (w) is a cooling consumption unit (kg/m<3> deg.C, the empirical value of the amt. of the liquefied gas required for cooling 1m<3> concrete by 1 deg.C); V is the amt. of concrete (m<3> ) at every batch; T1 is the actually measured temp. value ( deg.C) at the time of finishing kneading concrete; T0 is the target temp. ( deg.C) for kneading the concrete. Next, the concrete is kneaded by supplying the liquefied gas thereto at the supplying amt. W0 kg and the temp. tn for kneading the concrete is kept measured by each of the respective batches. The temp. differenceΔt from the previous batch is determined from these measured values. The correction rateΔW(kg) for the amt. of the liquefied gas to be supplied is calculated by equation II whenΔt exceeds the set range. The charging amt. W1 of the next time is set by increasing or decreasing the correction valueΔW to and from W0 like equation III. Henceforce, the supplying amt. of the next time is set by increasing or decreasing the correction valueΔW to and from the corrected Wn .