💡 How to use this lesson

Word	Meaning	Common collocations	Word forms	Example sentence	Memory tip
Materials and tools
binder	substance that holds materials together	chemical binder, strong binder	–	Add a strong binder to hold the aggregate together.	Think of a book binder holding pages together.
aggregate	crushed stone or sand mixed with cement	coarse aggregate, fine aggregate	–	Crushed stone is a common aggregate in concrete.	Picture an aggregate of small rocks gathered together.
slab	a thick, flat piece of solid material	concrete slab, heavy slab	–	Workers poured liquid mix to create a concrete slab.	Slab sounds like a heavy slab of stone dropping flat.
trowel	a flat hand tool used to smooth cement	steel trowel, smooth with a trowel	–	Use a steel trowel to make the top layer smooth.	Trowel sounds a bit like towel: you wipe the wet top smooth with it.
Changing
thicken	to become or make less liquid and more solid	thicken quickly, begin to thicken	thick (adj)	The wet mix will thicken in ten minutes.	Thicken comes from thick: making something thick.
dampen	to make something slightly wet	dampen the surface, slightly dampen	damp (adj)	Dampen the ground before you pour the concrete mix.	Dampen comes from damp: making something slightly damp.
flatten	to make something level and flat	flatten the mixture, flatten evenly	flat (adj)	Use a board to flatten the wet top layer.	Flatten comes from flat: making a surface flat.
The result
brittle	hard but easy to break or crack	become brittle, brittle material	–	Cold weather can make cheap concrete brittle.	Brittle sounds like breakable glass or dry twigs breaking.
solid	hard and firm, not liquid or hollow	solid rock, remain solid	–	The soft mix becomes solid after twenty-four hours.	Solid is firm like a solid block of ice.
weaken	to make something less strong	weaken the structure, weaken over time	weak (adj)	Adding too much water will weaken the final wall.	Weaken comes from weak: making something weak.

PART 1

Collocation Matrix: Verbs against Nouns

Worker A: "How do we prepare the dusty ground before pouring?"

Worker B: "First, ____ the surface with a light water spray."

Leave the wet mixture in the container for ten minutes; it will begin to ____ as it turns into a heavy paste.

Worker A: "The top layer of this floor looks uneven."

Worker B: "Use a long straight board to ____ the wet top surface evenly."

After sitting undisturbed for twenty-four hours, the liquid concrete becomes completely ____ and ready to support heavy loads.

____ a. weaken ____ b. dampen ____ c. flatten

____ a. solid ____ b. brittle ____ c. thick

____ a. trowel ____ b. binder ____ c. slab

____ a. aggregate ____ b. trowel ____ c. binder

The concrete mix needs more water because the liquid paste is too ____ to pour cleanly. (thicken)

Do not lay heavy stones on soil that is still ____ from recent heavy rain. (dampen)

Make sure the wooden base board is completely ____ before you pour the mix onto it. (flatten)

The outer wall broke early because the cheap cement mix was too ____ to withstand wind. (weaken)