A brief summary of what has been reported in the literature is given below:
The evaluation of clay wastes (CW) containing boron additives in ordinary Portland Cement (OPC) with different proportions (0%–20%) was done on the mechanical properties of mortar by the fresh and hardened concrete tests.
[I]On comparing with Turkish Standards (TS), it was concluded that strength values of all specimens containing 1.5% of CW were higher than that of the control sample.
[II]With the replacement of 2.5–5.0% of OPC by CW, the strength values were nearly equal to that of control sample.
[III]The durability properties increased (tested by the weight losses of samples exposed toNaCl and MgSO4 solutions) but mechanical properties decreased.
[IV] Four B-containing wastes (BW), [Sieve (SBW), Dewatering (DBW), Thickener (TBW) and Mixture (MBW)] wastes obtained from Kirka Boron plant in Turkey were investigated for the formation of artificial lightweight aggregates (LWA). The characterisation involved chemical, mineralogical and thermal analyses as well as testing of their bloating behaviour by means of heating microscopy. It was found that SBW and DBW present bloating behaviour whereas TBW and MBW do not.
Following the above results ,two mixtures M1 and M2 were prepared with (in wt.%): 20 clay mixture, 40 SBW, 40 DBW and 20 clay mixture, 35 SBW, 35 DBW, 10 quartz sand, respectively. Two different firing modes were applied: (a) from room temperature till 760 °C and (b) abrupt heating at 760 °C. The obtained bulk density for M1 and M2 pellets is 1.2g/ cm^3 and 0.9 g/cm^3, respectively.
The analysis of microstructure with electron microscopy revealed a glassy phase matrix and an extended formation of both interconnected and isolated, closed pores. The results indicate that SBW and DBW boron-containing wastes combined with a clay mixture and quartz sand can be valorized for the manufacturing of lightweight aggregates.
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